US8784339B2 - Spinal instrument for measuring load and position of load - Google Patents

Abstract

A spinal instrument includes sensors for measuring a parameter of the muscular-skeletal system. The spinal instrument includes a sensored head region that can be inserted into a spinal region. The spinal instrument comprises a housing, a housing, an electronic assembly, and a flexible interconnect. Housing includes a handle portion, a shaft portion, and a support structure. Similarly, housing includes a handle portion, a shaft portion, and a support structure. Furthermore, housing has a cavity and a lengthwise passage respectively for receiving electronic assembly and flexible interconnect. A sensored head region of spinal instrument includes an assembly stack for measuring load magnitude and position of load on the support structure and the support structure. The flexible interconnect couples the electronic assembly to the sensors.

Description

FIELD

The present invention pertains generally to surgical electronics, and particularly to methods and devices for assessing alignment and surgical implant parameters during spine surgery and long-term implantation.

BACKGROUND

The spine is made up of many individual bones called vertebrae, joined together by muscles and ligaments. Soft intervertebral discs separate and cushion each vertebra from the next. Because the vertebrae are separate, the spine is flexible and able to bend. The vertebrae provide a conduit for the spinal cord neural bundle. Together the vertebrae, discs, nerves, muscles, and ligaments make up the vertebral column or spine. The spine varies in size and shape, with changes that can occur due to environmental factors, health, and aging. The healthy spine has front-to-back curves, but deformities from normal cervical lordosis, thoracic kyphosis, and lumbar lordosis conditions can cause pain, discomfort, and difficulty with movement. These conditions can be exacerbated by herniated discs, which can pinch nerves.

There are many different causes of abnormal spinal curves and various treatment options from therapy to surgery. The goal of the surgery is a usually a solid fusion of two or more vertebrae in the curved part of the spine. A fusion is achieved by operating on the spine and adding bone graft. The vertebral bones and bone graft heal together to form a solid mass of bone called a fusion. Alternatively, a spinal cage is commonly used that includes bone graft for spacing and fusing vertebrae together. The bone graft may come from a bone bank or the patient's own hipbone or other autologous site. The spine can be substantially straightened with metal rods and hooks, wires or screws via instrumented tools and techniques. The rods or sometimes a brace or cast hold the spine in place until the fusion has a chance to heal.

BRIEF DESCRIPTION OF THE DRAWINGS

Various features of the system are set forth with particularity in the appended claims. The embodiments herein, can be understood by reference to the following description, taken in conjunction with the accompanying drawings, in which:

FIG. 1 illustrates a spine measurement system in accordance with an example embodiment;

FIG. 2 illustrates a spinal instrument in a non-limiting example;

FIG. 3 illustrates a spinal instrument having integrated electronics in a non-limiting example;

FIG. 4 illustrates an insert instrument with vertebral components in a non-limiting example;

FIG. 5 illustrates a lateral view of the spinal instrument positioned between vertebrae of the spine for sensing vertebral parameters in a non-limiting example;

FIG. 6 illustrates a graphical user interface (GUI) showing an axial view of the spinal instrument ofFIG. 5 in accordance with an example embodiment;

FIG. 7 illustrates the spinal instrument positioned between vertebra of the spine for intervertebral position and force sensing in accordance with an example embodiment;

FIG. 8 illustrates a user interface showing the spinal instrument ofFIG. 7 in accordance with an example embodiment;

FIG. 9 illustrates a lateral view of the spinal insert instrument for placement of the spine cage in accordance with an example embodiment;

FIG. 10 illustrates the graphical user interface showing the insert instrument ofFIG. 9 in a non-limiting example;

FIG. 11 is a block diagram of the components of the spinal instrument in accordance with an example embodiment;

FIG. 12 is a diagram of an exemplary communications system for short-range telemetry in accordance with an example embodiment;

FIG. 13 illustrates a communication network for measurement and reporting in accordance with an example embodiment;

FIG. 14 illustrates an exemplary diagrammatic representation of a machine in the form of a computer system within which a set of instructions, when executed, may cause the machine to perform any one or more of the methodologies disclosed herein;

FIG. 15 illustrates components of a spinal instrument in accordance with an example embodiment;

FIG. 16 illustrates a spine measurement system for providing intervertebral load and position of load data in accordance with an example embodiment;

FIG. 17 illustrates a spine measurement system for providing intervertebral load and position of load data in accordance with an example embodiment;

FIG. 18 illustrates an exploded view of the module and the handle in accordance with an example embodiment;

FIG. 19 illustrates a shaft for receiving a removable sensored head in accordance with an example embodiment;

FIG. 20 illustrates a cross-sectional view of a female coupling of the sensored head in accordance with an example embodiment;

FIG. 21 illustrates an exploded view of a spinal instrument in accordance with an example embodiment;

FIG. 22 illustrates a cross-sectional view a shaft region of the spinal instrument ofFIG. 21 in accordance with an example embodiment;

FIG. 23 illustrates a cross-sectional view of a sensored head region of the spinal instrument ofFIG. 21 in accordance with an example embodiment;

FIG. 24 illustrates an exploded view of the sensored head region of the spinal instrument ofFIG. 21; and

FIG. 25 illustrates a cross-sectional view of the sensored head region of the spinal instrument ofFIG. 21 in accordance with an example embodiment.

DETAILED DESCRIPTION

While the specification concludes with claims defining the features of the embodiments of the invention that are regarded as novel, it is believed that the method, system, and other embodiments will be better understood from a consideration of the following description in conjunction with the drawing figures, in which like reference numerals are carried forward.

As required, detailed embodiments of the present method and system are disclosed herein. However, it is to be understood that the disclosed embodiments are merely exemplary, which can be embodied in various forms. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a basis for the claims and as a representative basis for teaching one skilled in the art to variously employ the embodiments of the present invention in virtually any appropriately detailed structure. Further, the terms and phrases used herein are not intended to be limiting but rather to provide an understandable description of the embodiment herein.

Broadly stated, embodiments of the invention are directed to a system and method for vertebral load and location sensing. A spine measurement system comprises a spinal instrument coupled to a remote display. The spine measurement system can measure load, balance, and alignment to assess load forces on the vertebra. The spinal instrument can be an active device having an electronic assembly and a sensorized head assembly that can articulate within a vertebral space. The sensorized head can be inserted between vertebra and report vertebral conditions such as force, pressure, orientation and edge loading. The spine measurement system further includes alignment circuitry. The alignment circuitry provides positional information for identifying an orientation and location of the spinal instrument. A GUI of the remote system can be used to show where the spine instrument is positioned relative to vertebral bodies as the instrument is placed in the inter-vertebral space during the surgical procedure. The system can report optimal prosthetic size and placement in view of the sensed load and location parameters including optional orientation, rotation and insertion angle along a determined insert trajectory.

An insert instrument is also provided herein with the load balance and alignment system for inserting a vertebral component such as a spine cage or pedicle screw. The system in view of previously captured parameter measurements can check and report if the instrument is edge loading during an insertion. It shows tracking of the insert instrument with the vertebral component and provides visual guidance and feedback based on positional and load sensing parameters. The system shows three-dimensional (3D) tracking of the insert instrument in relation to one or more vertebral bodies whose orientation and position are also modeled in 3D.

FIG. 1 illustrates aspine measurement system100 in a non-limiting example. Thesystem100 comprises aspinal instrument102 that can be communicatively coupled to aremote system105. Thespine measurement system100 can further include alignment circuitry103 to determine positional information of at least one of an orientation, rotation, angle, and location. The positional information can relate to a tool, device, equipment, patient, or region of the muscular-skeletal system. In the example, alignment circuitry103 can be part ofspinal instrument102 or comprise external components. In one embodiment, external components comprising alignment circuitry103 can couple tospinal instrument102 or to regions of the spine for determining positional information. In one embodiment, location and position can be determined via one or more accelerometers. Alternatively, location and position can be determined via a time of flight or differential time of flight of a signal. The positional information can include orientation and translation data used to assess an alignment of thespine112. The positional information can be measured in real-time during the procedure or provided toremote system105.

In the example,spinal instrument102 can be used intra-operatively to measure a parameter of the spinal region.Spinal instrument102 includes at least one sensor for measuring the parameter.Spinal instrument102 can have more than one sensor for measuring different parameters and providing quantitative data to the surgeon in real-time. In one embodiment,spinal instrument102 measures load, position of load, and alignment.Spinal instrument102 is not limited to load and alignment measurement example. Other sensor types for measuring different parameters can be integrated into the device. The quantitative data generated byspinal instrument102 can be used to determine a location for placing a prosthetic component such as a pedicle screw or a spine cage in the spine.Spinal instrument102 can be used to distract the spinal region being measured. In general,spinal instrument102 and alignment circuitry103 may be used within asterile field109 of an operating room. Thesterile field109 can also be called a surgical field where a patient operation is performed. Typically,remote system105 is outside thesterile field109 of the operating room. Theremote system105 can be a laptop, mobile workstation, display or other device that presents a Graphical User Interface (GUI)107. In one embodiment,GUI107 contains a workflow that shows thespine112 and reports spinal instrument quantitative measurement data. For example, remote system can receive and display load, load position, and alignment data fromspinal instrument102 and alignment circuitry103. Alternatively,spinal instrument102 can have an interface for displaying or indicating the quantitative measurement data. In the example, thespinal instrument102 is a self-contained device for generating measurement data.

TheGUI107 is presented by way of theremote system105 andspine measurement system100. In the example, theGUI107 may have more than one window to show the quantitative measurement data provided byspinal instrument102 and alignment circuitry103.GUI107 is shown on the display ofremote system105 for providing real-time quantitative data fromspinal instrument107 and alignment circuitry103. In the example,spinal instrument102 is being directed to a spinal region. More specifically,spinal instrument102 is being directed between vertebrae of the spine. Sensors can be placed within a sensored head ofspinal instrument102. The sensored head can be used to distract the vertebrae thereby generating a gap between vertebrae that is the height of the sensored head.Spinal instrument102 can be wired or wirelessly coupled toremote system105. In the example,spinal instrument102 is wirelessly coupled toremote system105 for transmitting data. That transmitted data can include load, location, and position data.GUI107 can display alignment data in real-time such as shaft angle and a rotation component corresponding to the direction ofspinal instrument102 in relation to the vertebrae of interest. Furthermore,GUI107 can provide quantitative measurement data on the load and position of load applied by the vertebrae to the sensored head ofspinal instrument102 after insertion. Thus,measurement system100 allows the surgeon and medical staff to visualize use of thespinal instrument102 and the sensed parameters.

Thespine measurement system100 can be communicatively coupled to adatabase123 system such as aserver125 to provide three-dimensional (3D) imaging (e.g., soft tissue) and 3D models (e.g., bone) captured prior to, or during, surgery. The 3D imaging and models can be used in conjunction with positional information measured during the procedure to establish relative location and orientation. Theserver125 may be local in near vicinity or remotely accessed over theInternet121. As one example, theserver125 provides 3D spine and vertebra models. A CAT scanner (not shown) can be employed to produce a series of cross-sectional x-ray images of a selected part of the body. A computer operates the scanner, and the resulting picture represents a slice of the body. Theserver125 produces a three-dimensional (3D) model from the slices. Theserver125 can also provide 3D models generated from Magnetic Resonance Imaging (MRI) scanners (not shown). Theserver125 may also support fluoroscopic imaging to provide real-time moving images of the internal structures of a patient with respect to thespine measurement system100 devices through the use of X-ray source (not shown) and fluorescent screen.

In the example, the sensored head ofspinal instrument102 includes a sensor for measuring load. In one embodiment, the sensored head includes more than one sensor for measuring a location of an applied force, pressure, or load to the surfaces of the sensored head. Measuring the location of the applied force to surfaces of the sensored head ofspinal instrument102 provides information related to the spinal region and the distribution of the force. For example, an application may require an even distribution of force applied over a large area of the surfaces of the sensored head. Conversely, an application may require a peak force applied over a small area of the surface of the sensored head. In either example,spinal instrument102 can provide measurement data related to force magnitude and location of the applied force whereby the surgeon uses the quantitative data in conjunction with subjective information for assessing the probed spinal region.

Many physical parameters of interest within physical systems or bodies can be measured by evaluating changes in the characteristics of energy waves or pulses. As one example, changes in the transit time or shape of an energy wave or pulse propagating through a changing medium can be measured to determine the forces acting on the medium and causing the changes. The propagation velocity of the energy waves or pulses in the medium can be affected by physical changes in of the medium. The physical parameter or parameters of interest can include, but are not limited to, measurement of load, force, pressure, displacement, density, viscosity, and localized temperature. These parameters can be evaluated by measuring changes in the propagation time of energy pulses or waves relative to orientation, alignment, direction, or position as well as movement, rotation, or acceleration along an axis or combination of axes by wireless sensing modules or devices positioned on or within a body, instrument, equipment, or other mechanical system. Alternatively, measurements of interest can be taken using film sensors, mechanical sensors, polymer sensors, mems devices, strain gauge, piezo-resistive structure, and capacitive structures to name but a few.

FIG. 2 illustrates aspinal instrument400 in a non-limiting example. A side view and a top view are presented.Spinal instrument400 is a more detailed illustration of a non-limiting example ofspinal instrument102 ofFIG. 1.Spinal instrument400 comprises ahandle409, ashaft430, and asensored head407. Thehandle409 is coupled at a proximal end of theshaft430.Sensored head407 is coupled to a distal end of theshaft430. A surgeon holdsspinal instrument400 by thehandle409 todirect shaft430 andsensored head407 to a spinal region. In one embodiment, handle409,shaft430, andsensored head407 form a rigid structure that has little flex. Alternatively, one or more ofhandle409,shaft430, andsensored head407 may have some flexibility.Spinal instrument400 includes anelectronic assembly401 operatively coupled to one or more sensors. The sensors can be coupled tosurfaces403/406 on movingcomponents404/405 ofsensored head407.Electronic assembly401 can be located towards the proximal end of theshaft407 or inhandle409. As shown, theelectronic assembly401 is a module that is coupled toshaft409.Electronic assembly401 comprises electronic circuitry that includes logic circuitry, an accelerometer, and communication circuitry. The electronic circuitry controls sensor measurement, receives measurement data, stores the data, and can send the data to an external device.

In one embodiment, surfaces403 and406 ofsensored head407 can have a convex shape. The convex shape ofsurfaces403 and406 support placement ofsensored head407 within the spinal region and more specifically between the contours of vertebrae. In one embodiment,sensored head407 is height adjustable by way of thetop component404 and thebottom component405 through ajack402 that evenly distracts and closes according to handle409turning motion411.Jack402 is coupled to interior surfaces ofcomponents404 and405 ofsensored head407.Shaft430 includes one or more lengthwise passages. For example, interconnect such as a flexible wire interconnect can couple through one lengthwise passage ofshaft430 such thatelectronic assembly401 is operatively coupled to one or more sensors insensored head407. Similarly, a threaded rod can couple through a second passage ofshaft430 forcoupling handle409 to jack404 thereby allowing height adjustment ofsensored head407 via rotation ofhandle409.

Spine instrument400 can also determine location and orientation by way of one or more embedded accelerometers. Thesensored head407 supports multiple functions that include the ability to determine a parameter of the procedure area (e.g., intervertebral space) including pressure, tension, shear, load, torque, bone density, and/or bearing weight. In one embodiment, more than one load sensor can be included withinsensored head407. The more than one load sensors can be coupled to predetermined locations ofsurfaces403 and406. Having more than one load sensor allows thesensored head407 to measure load magnitude and the position of applied load tosurfaces403 and406. Thesensored head407 can be used to measure, adjust, and test a vertebral joint prior to installing a vertebral component. As will be seen ahead,measurement system100 can evaluate the optimal insertion angle and position ofspinal instrument400 during intervertebral load sensing. Themeasurement system100 can replicate insertion angle and position forinstrument400 or for another tool such as an insertion instrument.

In the present invention these parameters can be measured with an integrated wireless sensoredhead407 or device comprising an i) encapsulating structure that supports sensors and contacting surfaces and ii) an electronic assemblage that integrates a power supply, sensing elements, ultrasound resonator or resonators or transducer or transducers and ultrasound waveguide or waveguides, biasing spring or springs or other form of elastic members, an accelerometer, antennas and electronic circuitry that processes measurement data as well as controls all operations of energy conversion, propagation, and detection and wireless communications.Sensored head407 orinstrument400 can be positioned on or within, or engaged with, or attached or affixed to or within, a wide range of physical systems including, but not limited to instruments, appliances, vehicles, equipments, or other physical systems as well as animal and human bodies, for sensing and communicating parameters of interest in real time.

Spinal instrument400 can be used in the installation of a spinal cage as a non-limiting example. The spinal cage is used to space vertebrae in replacement of a disc. The spinal cage is typically hollow and can be formed having external threads for fixation. Two or more cages are often installed between the vertebrae to provide sufficient support and distribution of loading over the range of motion. In one embodiment, the spinal cage may be made of titanium for supporting spinal load and spacing between vertebrae. A bone growth material can also be placed in the cage to initiate and promote bone growth thereby further strengthening the intervertebral area long-term.Spinal instrument400 can be used to provide quantitative data such as load and position of load for a region between vertebrae that may be a candidate for a prosthetic component such as the spinal cage. Typically,spinal instrument400 is inserted in a gap selected by the surgeon between vertebrae.Spinal instrument400 measures load and position of load that can be viewed on an interface on the device or to a remote system such as that disclosed inFIG. 1. The position of load corresponds to the vertebral area surfaces applying the load onsurfaces403 or406 ofsensored head407. The angle and position of insertion of thesensored head407 ofspinal instrument400 can also be measured. The load magnitude and position of load measurement are used by the surgeon to determine an implant location between the vertebrae and the size of the spinal cage for the implant location. Typically, the height and length of the selected spinal cage is approximately the height and length ofsensored head407. Moreover, the area chosen for the spinal cage location may load the prosthetic component within a predetermined load range as measured byspinal instrument400. Conversely, quantitative measurements of vertebral loading outside the predetermined range may be found unsuitable for prosthetic component installation. The surgeon can modify the contact surfaces of the vertebrae to fall within the predetermined range as measured byspinal instrument400. The surgeon can also locate a different region between the vertebrae that is more suitable based on quantitative data provided byspinal instrument400.

In the example, a spinal cage is inserted in the measured region after removing thesensored head407. The spinal cage can be inserted in the same location measured bysensored head407 using quantitative measurement data. The alignment data ofspinal instrument400 is generated and recorded during an insertion process and measurement of load and position of load. The loading on the implanted spinal cage when inserted in the same position and angle assensored head407 is approximately equal to the measurements made byspinal instrument400. The recorded angle and position measurements can be subsequently used to guide the spinal cage into the same location and more specifically by a similar insertion path asspinal instrument400. In one embodiment,spinal instrument400 can be used to place the prosthetic component into the identified region. A separate instrument can also be used for insertion of the prosthetic component.

FIG. 3 illustrates aspinal instrument410 having integrated electronics in a non-limiting example.Spinal instrument410 is a more detailed illustration of a non-limiting example ofspinal instrument102 ofFIG. 1 and relates tospinal instrument400.Electronic assembly401 is placed withinhandle415 ofspinal instrument410. Placingelectronic assembly401 inhandle415 provides the benefit of isolating the circuitry from the external environment. Handle415 can further provide shock isolation for theelectronic assembly401 for reliability. In one embodiment, an externalwireless energy source414 can be placed in proximity to a charging unit withinelectronic assembly401 to initiate a wireless power recharging operation. Thewireless energy source414 can include a power supply, a modulation circuit, and a data input. The power supply inenergy source414 can be a battery, a charging device, a capacitor, a power connection, or other energy source for generating wireless power signals that can transfer power tospinal instrument410. The externalwireless energy source414 can transmit energy in the form of, but not limited to, electromagnetic induction, or other electromagnetic or ultrasound emissions. In at least one exemplary embodiment, the wireless energy source includes a coil to electromagnetically couple and activate (e.g., power on) with an induction coil in sensing device when placed in close proximity.

Electronic assembly401 operatively couples to sensors insensored head407 for measuring a parameter.Electronic assembly401 includes communication circuitry for transmitting measured parameter data to a receiver via data communications circuitry. The received parameter data can be processed remotely to permit visualization of the level and distribution of the parameter at various points on the sensored head. Information can also be provided toelectronic assembly401 using externalwireless energy source414. Data can be provided through an interface or port to externalwireless energy source414. The information or data can be input from another data source, such as from a computer via a wired or wireless connection (e.g., USB, IEEE802.16, etc.). In one embodiment, externalwireless energy source414 includes a modulation circuitry that can modulate the input information onto the power signals for sourcing energy toelectronic assembly401. In the example,electronic assembly401 has demodulation circuitry coupled for removing and providing the information for use byspinal instrument410 from the power signals.

FIG. 4 illustrates aninsert instrument420 with vertebral components in a non-limiting example.Electronic assembly401 as described herein supports the generation of orientation and position data ofinsert instrument420. In one embodiment,electronic assembly401 includes an accelerometer for providing orientation and position data. Referring toFIG. 11 briefly,electronic assembly401 ofinsert instrument420 can have more or less circuitry than that disclosed forspinal instruments400 and410. By way ofmeasurement system100, the user can replicate the insertion angle, position and trajectory (path) to achieve proper or pre-planned placement of a vertebral component.Insert instrument420 comprises ahandle432, ashaft434, and atip451. An attach/release mechanism455 couples to the proximal end ofshaft434 for controllingtip451. Attach/release mechanism455 allows a surgeon to retain or release vertebral components coupled totip451. Attach/release mechanism455 can mechanically couple throughshaft434 to controltip451. Alternatively, attach/release mechanism455 can be an electronic control. In the example, handle432 extends at an angle in proximity to a proximal end ofshaft434. Positioning ofhandle432 allows the surgeon to accuratelydirect tip451 in a spinal region while allowing access to attach/release mechanism455. Electronic assembly can be housed inhandle432 or attached to insertinstrument420. Referring toFIG. 12 briefly,electronic assembly401 includes communication circuitry to securely transmit and receive data from a remote system.Insert instrument420 is a tool ofspine measurement system100. Quantitative measurement data such as orientation and position data can be transmitted toremote system105 ofFIG. 1 for real time and visualization of an insertion process.Electronic assembly401 can also couple to one or more sensors ofinsert instrument420. In a first example,tip451 can be coupled to a pressure sensor to determine a force, pressure, or load being applied by the spinal region to a prosthetic component coupled thereto. In a second example,tip451 can be removable such that a sensored head can be coupled to insertinstrument420. In a third example, the prosthetic component can include a sensor. The sensor of the prosthetic component includes an interface that couples toelectronic assembly401 for providing quantitative measurement data.

In the illustration, an example prosthetic component is aspine cage475.Spine cage475 is a small hollow device, usually made of titanium, with perforated walls that can be inserted between the vertebrae of the spine during a surgery. In general, a distraction process spaces the vertebrae to a predetermined distance prior insertion ofspine cage475.Spine cage475 can increase stability, decrease vertebral compression, and reduce nerve impingement as a solution to improve patient comfort.Spine cage475 can include surface threads that allow the cage to be self-tapping and provide further stability.Spine cage475 can be porous to include bone graft material that supports bone growth between vertebral bodies throughcage475. More than one spine cage can be placed between vertebrae to alleviate discomfort. Proper placement and positioning ofspine cage475 is important for successful long-term implantation and patient outcome. As mentioned above, the orientation and position ofinsert instrument420 can be tracked in real-time in relation to the spinal region of interest. In one embodiment, the orientation and position being tracked is a prosthetic component retained byinsert instrument420. In the example, the prosthetic component isspine cage475.Spine cage475 can be tracked in 3D space because the location of the prosthetic component is known in relation to thespinal instrument420 and the one or more measurement accelerometers therein.

In the illustration a second prosthetic component is apedicle screw478. Thepedicle screw478 is a particular type of bone screw designed for implantation into a vertebral pedicle. There are two pedicles per vertebra that couple to other structures (e.g. lamina, vertebral arch). A polyaxial pedicle screw may be made of titanium to resist corrosion and increase component strength. The pedicle screw length ranges from 30 mm to 60 mm. The diameter ranges from 5.0 mm to 8.5 mm. It is not limited to these dimensions, which serve as dimensional examples.Pedicle screw478 can be used in instrumentation procedures to affix rods and plates to the spine to correct deformity, and/or treat trauma. It can be used to immobilize part of the spine to assist fusion by holding bony structures together. By way of electronic assembly401 (which may be internally or externally integrated), theinsert instrument420 can determine depth and angle for screw placement and guide the screw therein. In the example, one or more accelerometers are used to provide orientation, rotation, angle, or position information oftip451 during an insertion process.

In one arrangement, thescrew478 is embedded with sensors. The sensors can transmit energy and obtain a density reading and monitor the change in density over time. As one example, themeasurement system100 can monitor and report healing of a fracture site. The sensors can detect the change in motion at the fracture site as well as the motion between the screw and bone. Such information aids in monitoring healing and gives the healthcare provider an ability to monitor vertebral weight bearing as indicated. The sensors can also be activated externally to send energy waves to the fracture itself to aid in healing.

FIG. 5 illustrates a lateral view ofspinal instrument400 positioned between vertebrae of the spine for sensing vertebral parameters in a non-limiting example. The illustration can also apply tospinal instrument410 and insertinstrument420. In general, a compressive force is applied tosurfaces403 and406 whensensored head407 is inserted into the spinal region. In one embodiment,sensored head407 includes two or more load sensors that identify magnitude vectors of loading onsurface403,surface406, or both associated with inter-vertebral force there between. In the example shown, thespinal instrument400 is positioned between vertebra (L5) and the Sacrum (S1) such that a compressive force is applied tosurfaces403 and406. One approach for inserting theinstrument400 is from the posterior (back side) through a minilaparotomy as an endoscopic approach may be difficult to visualize or provide good exposure. Another approach is from the anterior (front side) which allows the surgeon to work through the abdomen to reach the spine. In this way spine muscles located in the back are not damaged or cut; avoiding muscle weakness and scarring.Spinal instrument400 can be used with either the anterior or posterior spine approach.

Aspects of the sensorized components of thespine instrument400 are disclosed in U.S. patent application Ser. No. 12/825,638 entitled “System and Method for Orthopedic Load Sensing Insert Device” filed Jun. 29, 2010, and U.S. patent application Ser. No. 12/825,724 entitled “Wireless Sensing Module for Sensing a Parameter of the Muscular-Skeletal System” filed Jun. 29, 2010 the entire contents of which are hereby incorporated by reference. Briefly, thesensored head407 can measure forces (Fx, Fy, and Fz) with corresponding locations and torques (e.g. Tx, Ty, and Tz) and edge loading of vertebrae. The electronic circuitry401 (not shown) controls operation and measurements of the sensors insensored head407. Theelectronic circuitry401 further includes communication circuitry for short-range data transmission. It can then transmit the measured data to the remote system to provide real-time visualization for assisting the surgeon in identifying any adjustments needed to achieve optimal joint balancing.

A method of installing a component in the muscular-skeletal system is disclosed below. The steps of the method can be performed in any order. An example of placing a cage between vertebrae is used to demonstrate the method but the method is applicable to other muscular-skeletal regions such as the knee, hip, ankle, spine, shoulder, hand, arm, and foot. In a first step, a sensored head of a predetermined width is placed in a region of the muscular-skeletal system. In the example, the insertion region is between vertebrae of the spine. A hammer can be used to tap an end of the handle to provide sufficient force to insert the sensored head between the vertebrae. The insertion process can also distract the vertebrae thereby increasing a separation distance. In a second step, the position of the load applied to the sensored head is measured. Thus, the load magnitude and the position of the loading on the surfaces of the sensored head are available. How the load applied by the muscular-skeletal system is positioned on the surfaces of the sensored head can aid in determining stability of the component once inserted. An irregular loading applied to sensored head can predict a scenario where the applied forces thrust the component away from the inserted position. In general, the sensored head is used to identify a suitable location for insertion of the component based on quantitative data. In a third step, the load and position of load data from the sensored head is displayed on a remote system in real-time. Similarly, in a fourth step, the at least one of orientation, rotation, angle, or position is displayed on the remote system in real-time. Changes made in positioning the sensored head are reflected in data on the remote system display. In a fifth step, a location between vertebrae having appropriate loading and position is identified and the corresponding quantitative measurement data is stored in memory.

In a sixth step, the sensored head is removed. In a seventh step, the component is inserted in the muscular-skeletal system. As an example, the stored quantitative measurement data is used to support the positioning of the component in the muscular-skeletal system. In the example, the insertion instrument can be used to direct the component into the muscular-skeletal system. The insertion instrument is an active device providing orientation, rotation, angle, or position of the component as it is being inserted. The previously measured direction and location of the insertion of the sensored head can be used to guide the insertion instrument. In one embodiment, the remote system display can aid in displaying relational alignment of the insertion instrument and component to the previously inserted sensored head. The insertion instrument in conjunction with the system can provide visual, vocal, haptic or other feedback to further aid in directing the placement of the component. In general, the component being inserted has substantially equal height and length as the sensored head. Ideally, the component is inserted identical in location and position to the previously inserted sensored head such that the loading and position of load on the component is similar to the quantitative measurements. In an eighth step, the component is positioned identically to the previously inserted sensored head and released. The insertion instrument can then be removed from the muscular-skeletal system. In a ninth step, at least the sensored head is disposed of.

Thus, the sensored head is used to identify a suitable location for insertion of the component. The insertion is supported by quantitative measurements that include position and location. Furthermore, the approximate loading and position of loading on the component is known after the procedure has been completed. In general, knowing the load applied by the muscular-skeletal system and the position on the surfaces of the component can aid in determining stability of the component long-term. An irregular loading applied on the component can result in the applied forces thrusting the component away from the inserted position.

FIG. 6 illustrates a graphical user interface (GUI)500 showing a axial (top) view of the sensorized spinal instrument ofFIG. 5 in a non-limiting example. Thegraphical user interface500 is presented by way of theremote system105 andspine measurement system100 ofFIG. 1. Reference is made tospinal instrument400 ofFIG. 2 andmeasurement system100 ofFIG. 1. TheGUI500 illustrates an example of how data can be presented. TheGUI500 includes awindow510 and arelated window520. Thewindow520 shows thespine instrument400 andsensor head407 in relation tovertebrae522 under evaluation. In this example, a axial (top) view of the vertebra is shown. It indicates a shaft angle523 and arotation component524 which reveal the approach angle and rotation of thespine instrument400, for instance, as it is moved forward into the incision. Thewindow520 and corresponding GUI information is presented and updated in real-time during the procedure. It permits the surgeon to visualize use ofspinal instrument400 and the sensed parameters. Thewindow510 shows a sensing surface (403 or406) of thesensored head407. Across hair512 is superimposed on the sensor head image to identify the maximal point of force and location. It can also lengthen to show vertebral edge loading. Awindow513 reports the load force, for example, 20 lbs across the sensor head surface. This information is presented and updated in real-time during the procedure.

As previously noted,spine measurement system100 can be used intra-operatively to aid in the implantation of the prosthesis, instrumentation, and hardware by way of parameter sensing (e.g., vertebral load, edge loading, compression, etc.). Thespinal instrument400 can include a power source that can provide power for only a single use or procedure. In one embodiment, components such asspinal instrument400 can be disposed of after being used in a procedure. Theremote system105 can be placed outside the surgical field for use in different procedures and with different tools.

In the spine, the affects on the bony and soft tissue elements are evaluated by themeasurement system100, as well as the soft tissue (e.g., cartilage, tendon, ligament) changes during surgery, including corrective spine surgery. The sensors of a tool, device, or implant used during the operation (and post-operatively) can support the evaluation and visualization of changes over time and report dynamic changes. The sensors can be activated intra-operatively when surgical parameter readings are stored. Immediately post-operatively, the sensor is activated and a baseline is known.

Themeasurement system100 allows evaluation of the spine and connective tissue regarding, but not limited to bone density, fluid viscosity, temperature, strain, pressure, angular deformity, vibration, load, torque, distance, tilt, shape, elasticity, and motion. Because the sensors span a vertebral space, they can predict changes in the vertebral component function prior to their insertion. As previously noted, themeasurement system100 can be used to placespine instrument400 in the inter-vertebral space, where it is shown positioned relative to thevertebral body522. Once it is placed and visually confirmed in the vertebral center, thesystem100 reports any edge loading on the instrument which in turn is used to size a proper vertebral device and insertion plan (e.g., approach angle, rotation, depth, path trajectory). Examples of implant component function include bearing wear, subsidence, bone integration, normal and abnormal motion, heat, change in viscosity, particulate matter, kinematics, to name a few.

FIG. 7 illustratesspinal instrument400 positioned between vertebra of the spine for intervertebral position and force sensing in accordance with an example embodiment. Reference is made tospinal instrument400 ofFIG. 2 andmeasurement system100 ofFIG. 1. The illustration can also apply tospinal instrument410 ofFIG. 3 and insertinstrument420 ofFIG. 4. As shown,sensored head407 ofspinal instrument400 is placed between vertebrae L3 and vertebrae L4. Thespinal instrument400 distracts the L3 and L4 vertebrae the height ofsensored head407 and provides quantitative data on load magnitude and position of load. As mentioned previously, thespine measurement system100 can include alignment circuitry103. The alignment circuitry103 can comprise external devices such as awand510 and awand520.Wands510 and520 can include accelerometers or circuitry to generate signals for time of flight and differential time of flight measurements.Wands510 and520 are coupled to different areas of the spinal region. In one embodiment,spinal instrument400 includes circuitry that communicates withwand510 and awand520 to determine position and alignment.Wands510 and520 are coupled to different vertebra of the spine withspinal instrument400 positioned to be in line of sight with each wand. Along shaft514 is provided on each wand to permit placement within vertebra of the spine and also line up with other wands and anelectronic assembly401 of thespine instrument400.Wand510 tracks an orientation and position of vertebra L3, whilewand520 tracks an orientation and position of vertebra L4. This permits thespine measurement system100 to track an orientation and movement of thespine instrument400 relative to movement of the neighboring vertebra. Each wand can also be sensorized similar tospinal instrument400.Wands510 andwand520 respectively includes asensor512 and asensor513.Sensors512 and513 can transmit and receive positional information. In the example,electronic assembly401 in conjunction withwands510 and520 dually serves to resolve an orientation and position ofspinal instrument400 during the procedure. Thus,spine measurement system100 can simultaneously provide quantitative measurement data such as load and position of load, position and alignment ofspinal instrument400, and position and alignment of one or more regions of the spine.

FIG. 8 illustratesuser interface600 showing thespinal instrument400 ofFIG. 7 in accordance with an example embodiment. Reference is made tospinal instrument400 ofFIG. 2 andmeasurement system100 ofFIG. 1. The illustration can also apply tospinal instrument410 ofFIG. 3 and insertinstrument420 ofFIG. 4.User interface600 is presented by way of theremote system105 and spine measurement system100 (seeFIG. 1). TheGUI600 includes awindow610 and arelated window620. Thewindow620 showsspinal instrument400 andsensored head407 in relation to avertebral component622 under evaluation. In this example, a sagital view of the spine column is shown. It indicates ashaft angle623 and arotation component624 which reveal the approach angle and rotation ofspinal instrument400 andsensored head407. Thewindow620 and corresponding GUI information is presented and updated in real-time during the procedure. It permits the surgeon to visualizesensored head407 of thespinal instrument400 and the sensed load force parameters. Thewindow610 shows sensing surfaces of thesensor head407. Across hair612 is superimposed on the image ofsensored head407 to identify the maximal point of force and location. It can also adjust in width and length to show vertebral edge loading. AnotherGUI window613 reports the load force across thesensored head407 surface. TheGUI600 is presented and updated in real-time during the procedure.

FIG. 9 illustrates a lateral view ofspinal insert instrument420 for placement ofspine cage475 in accordance with an example embodiment. The illustration can also apply tospinal instrument400 ofFIG. 2 andspinal instrument410 ofFIG. 3 when adapted to retain components for insert installation.Insert instrument420 provides a surgical means for implanting vertebral component475 (e.g. spine cage, pedicle screw, sensor) between the L3 and L4 vertebrae in the illustration.Mechanical assembly tip451 at the distal end ofshaft434 permits attaching and releasing of the vertebral component by way of attach/release mechanism455. Thevertebral component475 can be placed in the back of the spine through a midline incision in the back, for example, via posterior lumbar interbody fusion (PLIF) as shown. Theinsert instrument420 can similarly be used in anterior lumbar interbody fusion (ALIF) procedures.

In one method herein contemplated, the position ofspine cage475 prior to insertion is optimally defined for example, via 3D imaging or via ultrasonic navigation as described with alignment circuitry103 ofFIG. 1 withspinal instrument400 shown inFIGS. 6 and 7. The load sensor407 (seeFIG. 7) is positioned between the vertebra to assess loading forces as described above where an optimal insertion path and trajectory is therein defined. The load forces and path of instrument insertion are recorded. Thereafter as shown inFIG. 9, insertinstrument420 inserts the finalspinal cage475 according to the recorded path ofspinal instrument400 and as based on the load forces. During the insertion, the GUI as shown inFIG. 10 navigates thespinal instrument420 to the recorded insertion point.Spinal insert instrument420 can be equipped with one or more load sensors serving as a placeholder to a final spinal cage. After placement ofspinal cage475 between the vertebra, release of the spine cage frominsert instrument420, and removal of theinsert instrument420, the open space occupied around the spinal cage is then closed down via rods and pedicle screws on the neighboring vertebra. This compresses the surrounding vertebra onto the spinal cage, and provides stability for verterbral fusion. During this procedure, theGUI700 ofFIG. 10 reports change in spinal anatomy, for example, Lordosis and Kyphosis, due to adjustment of the rods and tightening of the pedicle screws. Notably, theGUI700 also provides visual feedback indicating which the amount and directions to achieve the planned spinal alignment by way of instrumented adjustments to the rods and screws.

FIG. 10 illustrates graphical user interface (GUI)700 showing a lateral view of theinsert instrument420 ofFIG. 9 in a non-limiting example.GUI700 can be presented by way of theremote system105 andmeasurement system100 ofFIG. 1.GUI700 includes awindow710 and arelated window720. Thewindow720 shows insertinstrument420 andvertebral component475 in relation to the L4 and L5 vertebrae under evaluation. In this example, a sagital (side) view of the spine column is shown. It indicates ashaft angle723 and arotation component724 which reveal the approach angle and rotation ofinsert instrument420 andvertebral component475.Window720 and corresponding GUI information can be presented and updated in real-time during the procedure. The real-time display permits the surgeon to visualize thevertebral component475 of theinsert instrument420 according to the previously sensed load force parameters.

Window710 shows a target sensoredhead orientation722 and a currentinstrument head orientation767. Thetarget orientation722 shows the approach angle, rotation and trajectory path previously determined when thespine instrument400 was used for evaluating loading parameters. The currentinstrument head orientation767 shows tracking of theinsert instrument420 currently used to insert thespine cage475.GUI700 presents thetarget orientation model722 in view of the currentinstrument head orientation767 to provide visualization of the previously determined surgical plan.

Referring toFIGS. 1,5,6,7, and8,spinal instrument400 is used to assess procedural parameters (e.g., angle, rotation, path) in view of determined sensing parameters (e.g., load, force, edge). Referring back toFIG. 10, once these procedural parameters were determined,measurement system100 by way ofGUI700 now guides the surgeon withinsert instrument420 to insert the vertebral components475 (e.g., spine cage, pedicle screw). In one arrangement,measurement system100 provides haptic feedback to guideinsert instrument420 during the insertion procedure. For example, insertinstrument420 can vibrate when thecurrent approach angle713 deviates from the target approach angle, provides a visual cue (red/green indication), or when theorientation767 is not aligned with thetarget trajectory path722. The amount of feedback (e.g. haptic or visual) can correspond to the amount of deviation. Alternatively, vocal feedback can be provided bysystem100 to supplement the visual and haptic information being provided. TheGUI700 effectively recreates the position and target path ofinsert instrument420 through visual and haptic feedback based on the previous instrumenting. It is contemplated herein thatspinal instrument420 can also be adapted for both load measurement and an insertion process.

The loading, balance, and position can be adjusted during surgery within predetermined quantitatively measured ranges through surgical techniques and adjustments using data from sensorized devices disclosed herein for alignment and parameter throughmeasurement system100. Both the trial and final inserts (e.g., spine cage, pedicle screw, sensors, etc.) can include the sensing module to provide measured data to the remote system for display. A final insert can also be used to monitor the vertebral joint long term. The data can be used by the patient and health care providers to ensure that the vertebral joint or fused vertebrae is functioning properly during rehabilitation and as the patient returns to an active normal lifestyle. Conversely, the patient or health care provider can be notified when the measured parameters are out of specification. This provides early detection of a spine problem that can be resolved with minimal stress to the patient. The data from final insert can be displayed on a screen in real time using data from the embedded sensing module. In one embodiment, a handheld device is used to receive data from final insert. The handheld device can be held in proximity to the spine allowing a strong signal to be obtained for reception of the data.

A method is disclosed for inserting a prosthetic component in a spinal region in a non-limiting example. The method can be practiced with more or less than the number of steps shown and is not limited to the order shown. To describe the method, reference will be made toFIGS. 1,7, and9 although it is understood that the method can be implemented in any other manner using other suitable components. In a first step, the spinal region is distracted to create a gap or spacing. The distraction process produces a suitable spacing for receiving a prosthetic component. As disclosed herein, the distraction process can also generate quantitative data such as load and position of load measurements applied by the spinal region to a measurement device of similar size to the prosthetic component. In a second step, the prosthetic component is directed to the spinal region. In the example, an insert instrument is used by a surgeon to direct the prosthetic component held by the tool at a tip of the device. In a third step, the insert instrument measures at least one of orientation, rotation, angle, or position of the prosthetic component. The insert instrument can track a trajectory of the insert instrument and prosthetic component in real-time during the insertion process. In a fourth step, the insert instrument transmits data related to one of orientation, rotation, angle, or position of the prosthetic component and insert instrument. In the example, the data is transmitted wirelessly local to the procedure.

In a fifth step, the transmitted data from the insert instrument is displayed on a remote system. In the example, the remote system can be in the operating room where the procedure is being performed in view of the surgeon. The at least one of orientation, rotation, angle, or position measurement data can be displayed in a manner that allows visualization of the trajectory of the prosthetic component to the spinal region. The visualization allows the surgeon to better direct the prosthetic component where visibility to the region is limited. Furthermore, the visualization provides the benefit of placing the prosthetic component in a previously identified area and at a similar trajectory of the spinal region using quantitative measurement data. In a sixth step, the trajectory of the insert instrument and prosthetic component being tracked can be compared with a trajectory previously measured. The compared trajectories can be displayed and visualized on the display of the remote system.

In a seventh step, the prosthetic component is inserted into the spinal region. In the example, the prosthetic component is placed in the gap or spacing from the prior distraction process. The prosthetic component can be placed in approximately the same location and alignment of a prior device such as the spinal instrument disclosed herein. In an eighth step, the prosthetic component is released in the spinal region. The surgeon can view the placement of the prosthetic component on the remote display. The location and alignment of the prosthetic component is supported by the measurement data provided by the insert instrument. The attach/release mechanism is used to release the prosthetic component from the insert instrument. In a ninth step, the insert instrument is removed from the spinal region. In a tenth step, the insert instrument can be disposed of after the procedure is completed. Alternatively, the insert instrument can be sterilized for use in another procedure.

FIG. 11 is a block diagram of the components ofspinal instrument400 in accordance with an example embodiment. The block diagram can also apply tospinal instrument410 ofFIG. 3 and insertinstrument420 ofFIG. 4. It should be noted thatspinal instrument400 could comprise more or less than the number of components shown.Spinal instrument400 is a self-contained tool that can measure a parameter of the muscular-skeletal system. In the example, thespinal instrument400 measures load and position of load when inserted in a spinal region. The active components ofspinal instrument400 include one ormore sensors1602, aload plate1606, apower source1608,electronic circuitry1610, atransceiver1612, and anaccelerometer1614. In a non-limiting example, an applied compressive force is applied tosensors1602 by the spinal region and measured by thespinal instrument400.

Thesensors1602 can be positioned, engaged, attached, or affixed to thesurfaces403 and406 ofspinal instrument400. In general, a compressive force is applied by the spinal region tosurfaces403 and406 when inserted therein. Thesurfaces403 and406 couple tosensors1602 such that a compressive force is applied to each sensor. In one embodiment, the position of applied load tosurfaces403 and406 can be measured. In the example, three load sensors are used in the sensored head to identify position of applied load. Each load sensor is coupled to a predetermined position on theload plate1606. Theload plate1606 couples to surface403 to distribute a compressive force applied to the sensored head ofspinal instrument400 to each sensor. Theload plate1606 can be rigid and does not flex when distributing the force, pressure, or load tosensors1602. The force or load magnitude measured by each sensor can be correlated back to a location of applied load on thesurface403.

In the example of intervertebral measurement, the sensoredhead having surfaces403 and406 can be positioned between the vertebrae of the spine.Surface403 of the sensored head couples to a first vertebral surface and similarly thesurface406 couples to a second vertebral surface.Accelerometer1614 or an external alignment system can be used to measure position and orientation of the sensored head as it is directed into the spinal region. Thesensors1602 couple to theelectronic circuitry1610. Theelectronic circuitry1610 comprises logic circuitry, input/output circuitry, clock circuitry, D/A, and A/D circuitry. In one embodiment, theelectronic circuitry1610 comprises an application specific integrated circuit that reduces form factor, lowers power, and increases performance. In general, theelectronic circuitry1610 controls a measurement process, receives the measurement signals, converts the measurement signals to a digital form, supports display on an interface, and initiates data transfer of measurement data.Electronic circuitry1610 measures physical changes in thesensors1602 to determine parameters of interest, for example a level, distribution and direction of forces acting on thesurfaces403 and406. Theinsert sensing device400 can be powered by aninternal power source1608. Thus, all the components required to measure parameters of the muscular-skeletal system reside in thespinal instrument400.

As one example,sensors1602 can comprise an elastic or compressible propagation structure between a first transducer and a second transducer. The transducers can be an ultrasound (or ultrasonic) resonator, and the elastic or compressible propagation structure can be an ultrasound waveguide. Theelectronic circuitry1610 is electrically coupled to the transducers to translate changes in the length (or compression or extension) of the compressible propagation structure to parameters of interest, such as force. The system measures a change in the length of the compressible propagation structure (e.g., waveguide) responsive to an applied force and converts this change into electrical signals, which can be transmitted via thetransceiver1612 to convey a level and a direction of the applied force. For example, the compressible propagation structure has known and repeatable characteristics of the applied force versus the length of the waveguide. Precise measurement of the length of the waveguide using ultrasonic signals can be converted to a force using the known characteristics.

Sensors1602 are not limited to waveguide measurements of force, pressure, or load sensing. In yet other arrangements,sensors1602 can include piezo-resistive, compressible polymers, capacitive, optical, mems, strain gauge, chemical, temperature, pH, and mechanical sensors for measuring parameters of the muscular-skeletal system. In an alternate embodiment, a piezo-resistive film sensor can be used for sensing load. The piezo-resistive film has a low profile thereby reducing the form factor required for the implementation. The piezo-resistive film changes resistance with applied pressure. A voltage or current can be applied to the piezo-resistive film to monitor changes in resistance.Electronic circuitry1610 can be coupled to apply the voltage or current. Similarly,electronic circuitry1610 can be coupled to measure the voltage and current corresponding to a resistance of the piezo-resistive film. The relation of piezo-resistive film resistance to an applied force, pressure, or load is known.Electronic circuitry1610 can convert the measured voltage or current to a force, pressure, or load applied to the sensored head. Furthermore,electronic circuitry1610 can convert the measurement to a digital format for display or transfer for real-time use or for being stored.Electronic circuitry1610 can include converters, inputs, outputs, and input/outputs that allow serial and parallel data transfer whereby measurements and transmission of data can occur simultaneously. In one embodiment, an ASIC is included inelectronic circuitry1610 that incorporates digital control logic to manage control functions and the measurement process ofspinal instrument400 as directed by the user.

Theaccelerometer1614 can measure acceleration and static gravitational pull.Accelerometer1614 can be single-axis and multi-axis accelerometer structures that detect magnitude and direction of the acceleration as a vector quantity.Accelerometer1614 can also be used to sense orientation, vibration, impact and shock. Theelectronic circuitry1610 in conjunction with theaccelerometer1614 andsensors1602 can measure parameters of interest (e.g., distributions of load, force, pressure, displacement, movement, rotation, torque, location, and acceleration) relative to orientations ofspinal instrument400. In such an arrangement, spatial distributions of the measured parameters relative to a chosen frame of reference can be computed and presented for real-time display.

Thetransceiver1612 comprises atransmitter1622 and anantenna1620 to permit wireless operation and telemetry functions. In various embodiments, theantenna1620 can be configured by design as an integrated loop antenna. The integrated loop antenna is configured at various layers and locations on a printed circuit board having other electrical components mounted thereto. For example,electronic circuitry1610,power source1608,transceiver1612, andaccelerometer1614 can be mounted on a circuit board that is located on or inspinal instrument400. Once initiated thetransceiver1612 can broadcast the parameters of interest in real-time. The telemetry data can be received and decoded with various receivers, or with a custom receiver. The wireless operation can eliminate distortion of, or limitations on, measurements caused by the potential for physical interference by, or limitations imposed by, wiring and cables coupling the sensing module with a power source or with associated data collection, storage, display equipment, and data processing equipment.

Thetransceiver1612 receives power from thepower source1608 and can operate at low power over various radio frequencies by way of efficient power management schemes, for example, incorporated within theelectronic circuitry1610 or the application specific integrated circuit. As one example, thetransceiver1612 can transmit data at selected frequencies in a chosen mode of emission by way of theantenna1620. The selected frequencies can include, but are not limited to, ISM bands recognized in InternationalTelecommunication Union regions 1, 2 and 3. A chosen mode of emission can be, but is not limited to, Gaussian Frequency Shift Keying, (GFSK), Amplitude Shift Keying (ASK), Phase Shift Keying (PSK), Minimum Shift Keying (MSK), Frequency Modulation (FM), Amplitude Modulation (AM), or other versions of frequency or amplitude modulation (e.g., binary, coherent, quadrature, etc.).

Theantenna1620 can be integrated with components of the sensing module to provide the radio frequency transmission. Theantenna1620 andelectronic circuitry1610 are mounted and coupled to form a circuit using wire traces on a printed circuit board. Theantenna1620 can further include a matching network for efficient transfer of the signal. This level of integration of the antenna and electronics enables reductions in the size and cost of wireless equipment. Potential applications may include, but are not limited to any type of short-range handheld, wearable, or other portable communication equipment where compact antennas are commonly used. This includes disposable modules or devices as well as reusable modules or devices and modules or devices for long-term use.

Thepower source1608 provides power to electronic components of thespinal instrument400. In one embodiment,power source1608 can be charged by wired energy transfer, short-distance wireless energy transfer or a combination thereof. External power sources for providing wireless energy topower source1608 can include, but are not limited to, a battery or batteries, an alternating current power supply, a radio frequency receiver, an electromagnetic induction coil, a photoelectric cell or cells, a thermocouple or thermocouples, or an ultrasound transducer or transducers. By way ofpower source1608,spinal instrument400 can be operated with a single charge until the internal energy is drained. It can be recharged periodically to enable continuous operation. Thepower source1608 can further utilize power management techniques for efficiently supplying and providing energy to the components ofspinal instrument400 to facilitate measurement and wireless operation. Power management circuitry can be incorporated on the ASIC to manage both the ASIC power consumption as well as other components of the system.

Thepower source1608 minimizes additional sources of energy radiation required to power the sensing module during measurement operations. In one embodiment, as illustrated, theenergy storage1608 can include a capacitiveenergy storage device1624 and aninduction coil1626. The external source of charging power can be coupled wirelessly to the capacitiveenergy storage device1624 through the electromagnetic induction coil orcoils1626 by way of inductive charging. The charging operation can be controlled by a power management system designed into, or with, theelectronic circuitry1610. For example, during operation ofelectronic circuitry1610, power can be transferred from capacitiveenergy storage device1624 by way of efficient step-up and step-down voltage conversion circuitry. This conserves operating power of circuit blocks at a minimum voltage level to support the required level of performance. Alternatively,power source1608 can comprise one or more batteries that are housed withinspinal instrument400. The batteries can power a single use of thespinal instrument400 whereby the device is disposed after it has been used in a surgery.

In one configuration, the external power source can further serve to communicate downlink data to thetransceiver1612 during a recharging operation. For instance, downlink control data can be modulated onto the wireless energy source signal and thereafter demodulated from theinduction coil1626 by way ofelectronic circuitry1610. This can serve as a more efficient way for receiving downlink data instead of configuring thetransceiver1612 for both uplink and downlink operation. As one example, downlink data can include updated control parameters that thespinal instrument400 uses when making a measurement, such as external positional information, or for recalibration purposes. It can also be used to download a serial number or other identification data.

Theelectronic circuitry1610 manages and controls various operations of the components of the sensing module, such as sensing, power management, telemetry, and acceleration sensing. It can include analog circuits, digital circuits, integrated circuits, discrete components, or any combination thereof. In one arrangement, it can be partitioned among integrated circuits and discrete components to minimize power consumption without compromising performance. Partitioning functions between digital and analog circuit enhances design flexibility and facilitates minimizing power consumption without sacrificing functionality or performance. Accordingly, theelectronic circuitry1610 can comprise one or more integrated circuits or ASICs, for example, specific to a core signal-processing algorithm.

In another arrangement, theelectronic circuitry1610 can comprise a controller such as a programmable processor, a Digital Signal Processor (DSP), a microcontroller, or a microprocessor, with associated storage memory and logic. The controller can utilize computing technologies with associated storage memory such a Flash, ROM, RAM, SRAM, DRAM or other like technologies for controlling operations of the aforementioned components of the sensing module. In one arrangement, the storage memory may store one or more sets of instructions (e.g., software) embodying any one or more of the methodologies or functions described herein. The instructions may also reside, completely or at least partially, within other memory, and/or a processor during execution thereof by another processor or computer system.

The electronics assemblage also supports testability and calibration features that assure the quality, accuracy, and reliability of the completed wireless sensing module or device. A temporary bi-directional coupling can be used to assure a high level of electrical observability and controllability of the electronics. The test interconnect also provides a high level of electrical observability of the sensing subsystem, including the transducers, waveguides, and mechanical spring or elastic assembly. Carriers or fixtures emulate the final enclosure of the completed wireless sensing module or device during manufacturing processing thus enabling capture of accurate calibration data for the calibrated parameters of the finished wireless sensing module or device. These calibration parameters are stored within the on-board memory integrated into the electronics assemblage.

Applications for the electronic assembly comprising thesensors1602 andelectronic circuitry1610 may include, but are not limited to, disposable modules or devices as well as reusable modules or devices and modules or devices for long-term use. In addition to non-medical applications, examples of a wide range of potential medical applications may include, but are not limited to, implantable devices, modules within implantable devices, intra-operative implants or modules within intra-operative implants or trial inserts, modules within inserted or ingested devices, modules within wearable devices, modules within handheld devices, modules within instruments, appliances, equipment, or accessories of all of these, or disposables within implants, trial inserts, inserted or ingested devices, wearable devices, handheld devices, instruments, appliances, equipment, or accessories to these devices, instruments, appliances, or equipment.

FIG. 12 is a diagram of anexemplary communications system1700 for short-range telemetry in accordance with an exemplary embodiment. The illustration applies tospinal instrument400 ofFIG. 2,spinal instrument410 ofFIG. 3, insertinstrument420 ofFIG. 4, andspine measurement system100 ofFIG. 1. It should be noted thatcommunication system1700 may comprise more or less than the number of components shown. As illustrated, thecommunications system1700 comprises medicaldevice communications components1710 in a spinal instrument and receiving system communications in a processor based remote system. In one embodiment, the receiving remote system communications are in or coupled to a computer or laptop computer that can be viewed by the surgical team during a procedure. The remote system can be external to the sterile field of the operating room but within viewing range to assess measured quantitative data in real time. The medicaldevice communications components1710 are operatively coupled to include, but not limited to, theantenna1712, amatching network1714, atelemetry transceiver1716, aCRC circuit1718, adata packetizer1722, adata input1724, apower source1726, and an application specific integrated circuit (ASIC)1720. The medicaldevice communications components1710 may include more or less than the number of components shown and are not limited to those shown or the order of the components.

The receivingstation communications components1750 comprise anantenna1752, amatching network1754, atelemetry receiver1756, theCRC circuit1758, thedata packetizer1760, and optionally aUSB interface1762. Notably, other interface systems can be directly coupled to thedata packetizer1760 for processing and rendering sensor data.

Referring toFIG. 11, theelectronic circuitry1610 is operatively coupled to one or more sensors602 of thespinal instrument400. In one embodiment, the data generated by the one or more sensors602 can comprise a voltage, current, frequency, or count from a mems structure, piezo-resistive sensor, strain gauge, mechanical sensor, pulsed, continuous wave, or other sensor type that can be converted to the parameter being measured of the muscular-skeletal system. Referring back toFIG. 12, thedata packetizer1722 assembles the sensor data into packets; this includes sensor information received or processed byASIC1720. TheASIC1720 can comprise specific modules for efficiently performing core signal processing functions of the medicaldevice communications components1710. A benefit ofASIC1720 is in reducing a form factor of the tool.

TheCRC circuit1718 applies error code detection on the packet data. The cyclic redundancy check is based on an algorithm that computes a checksum for a data stream or packet of any length. These checksums can be used to detect interference or accidental alteration of data during transmission. Cyclic redundancy checks are especially good at detecting errors caused by electrical noise and therefore enable robust protection against improper processing of corrupted data in environments having high levels of electromagnetic activity. Thetelemetry transmitter1716 then transmits the CRC encoded data packet through thematching network1714 by way of theantenna1712. Thematching networks1714 and1754 provide an impedance match for achieving optimal communication power efficiency.

The receivingsystem communications components1750 receive transmissions sent by spinalinstrument communications components1710. In one embodiment,telemetry transmitter1716 is operated in conjunction with adedicated telemetry receiver1756 that is constrained to receive a data stream broadcast on the specified frequencies in the specified mode of emission. Thetelemetry receiver1756 by way of the receivingstation antenna1752 detects incoming transmissions at the specified frequencies. Theantenna1752 can be a directional antenna that is directed to a directional antenna ofcomponents1710. Using at least one directional antenna can reduce data corruption while increasing data security by further limiting the data is radiation pattern. Amatching network1754 couples toantenna1752 to provide an impedance match that efficiently transfers the signal fromantenna1752 totelemetry receiver1756.Telemetry receiver1756 can reduce a carrier frequency in one or more steps and strip off the information or data sent bycomponents1710.Telemetry receiver1756 couples toCRC circuit1758.CRC circuit1758 verifies the cyclic redundancy checksum for individual packets of data.CRC circuit1758 is coupled todata packetizer1760.Data packetizer1760 processes the individual packets of data. In general, the data that is verified by theCRC circuit1758 is decoded (e.g., unpacked) and forwarded to an external data processing device, such as an external computer, for subsequent processing, display, or storage or some combination of these.

Thetelemetry receiver1756 is designed and constructed to operate on very low power such as, but not limited to, the power available from thepowered USB port1762, or a battery. In another embodiment, thetelemetry receiver1756 is designed for use with a minimum of controllable functions to limit opportunities for inadvertent corruption or malicious tampering with received data. Thetelemetry receiver1756 can be designed and constructed to be compact, inexpensive, and easily manufactured with standard manufacturing processes while assuring consistently high levels of quality and reliability.

In one configuration, thecommunication system1700 operates in a transmit-only operation with a broadcasting range on the order of a few meters to provide high security and protection against any form of unauthorized or accidental query. The transmission range can be controlled by the transmitted signal strength, antenna selection, or a combination of both. A high repetition rate of transmission can be used in conjunction with the Cyclic Redundancy Check (CRC) bits embedded in the transmitted packets of data during data capture operations thereby enabling the receiving system to discard corrupted data without materially affecting display of data or integrity of visual representation of data, including but not limited to measurements of load, force, pressure, displacement, flexion, attitude, and position within operating or static physical systems.

By limiting the operating range to distances on the order of a few meters thetelemetry transmitter1716 can be operated at very low power in the appropriate emission mode or modes for the chosen operating frequencies without compromising the repetition rate of the transmission of data. This mode of operation also supports operation with compact antennas, such as an integrated loop antenna. The combination of low power and compact antennas enables the construction of, but is not limited to, highly compact telemetry transmitters that can be used for a wide range of non-medical and medical applications.

The transmitter security as well as integrity of the transmitted data is assured by operating the telemetry system within predetermined conditions. The security of the transmitter cannot be compromised because it is operated in a transmit-only mode and there is no pathway to hack into medical device communications components. The integrity of the data is assured with the use of the CRC algorithm and the repetition rate of the measurements. Limiting the broadcast range of the device minimizes the risk of unauthorized reception of data. Even if unauthorized reception of the data packets should occur there are counter measures in place that further mitigate data access. A first measure is that the transmitted data packets contain only binary bits from a counter along with the CRC bits. A second measure is that no data is available or required to interpret the significance of the binary value broadcast at any time. A third measure that can be implemented is that no patient or device identification data is broadcast at any time.

Thetelemetry transmitter1716 can also operate in accordance with some FCC regulations. According to section 18.301 of the FCC regulations the ISM bands within the USA include 6.78, 13.56, 27.12, 30.68, 915, 2450, and 5800 MHz as well as 24.125, 61.25, 122.50, and 245 GHz. Globally other ISM bands, including 433 MHz, are defined by the International Telecommunications Union in some geographic locations. The list of prohibited frequency bands defined in 18.303 are “the following safety, search and rescue frequency bands is prohibited: 490-510 kHz, 2170-2194 kHz, 8354-8374 kHz, 121.4-121.6 MHz, 156.7-156.9 MHz, and 242.8-243.2 MHz.

Section 18.305 stipulates the field strength and emission levels ISM equipment must not exceed when operated outside defined ISM bands. In summary, it may be concluded that ISM equipment may be operated worldwide within ISM bands as well as within most other frequency bands above 9 KHz given that the limits on field strengths and emission levels specified in section 18.305 are maintained by design or by active control. As an alternative, commercially available ISM transceivers, including commercially available integrated circuit ISM transceivers, may be designed to fulfill these field strengths and emission level requirements when used properly.

In one configuration, thetelemetry transmitter1716 can also operate in unlicensed ISM bands or in unlicensed operation of low power equipment, wherein the ISM equipment (e.g., telemetry transmitter1716) may be operated on ANY frequency above 9 kHz except as indicated in Section 18.303 of the FCC code.

Wireless operation eliminates distortion of, or limitations on, measurements caused by the potential for physical interference by, or limitations imposed by, wiring and cables coupling the wireless sensing module or device with a power source or with data collection, storage, or display equipment. Power for the sensing components and electronic circuits is maintained within the wireless sensing module or device on an internal energy storage device. This energy storage device is charged with external power sources including, but not limited to, a battery or batteries, super capacitors, capacitors, an alternating current power supply, a radio frequency receiver, an electromagnetic induction coil, a photoelectric cell or cells, a thermocouple or thermocouples, or an ultrasound transducer or transducers. The wireless sensing module may be operated with a single charge until the internal energy source is drained or the energy source may be recharged periodically to enable continuous operation. The embedded power supply minimizes additional sources of energy radiation required to power the wireless sensing module or device during measurement operations. Telemetry functions are also integrated within the wireless sensing module or device. Once initiated the telemetry transmitter continuously broadcasts measurement data in real time. Telemetry data may be received and decoded with commercial receivers or with a simple, low cost custom receiver.

FIG. 13 illustrates acommunication network1800 for measurement and reporting in accordance with an example embodiment. Briefly, thecommunication network1800 expands communication forspine measurement system100 ofFIG. 1,spinal instrument400 ofFIG. 2,spinal instrument410 ofFIG. 3, and insertinstrument420 to provide broad data connectivity to other devices or services. As illustrated,spinal alignment system100,spinal instrument400, and insertinstrument420 can be communicatively coupled to thecommunications network1800 and any associated systems or services. It should be noted thatcommunication network1800 can comprise more or less than the number of communication networks and systems shown.

As one example,measurement system100,spinal instrument400,spinal instrument410, and insertinstrument420 can share its parameters of interest (e.g., distributions of load, force, pressure, displacement, movement, rotation, torque and acceleration) with remote services or providers, for instance, to analyze or report on surgical status or outcome. In the case that a sensor system is permanently implanted, the data from the sensor can be shared for example with a service provider to monitor progress or with plan administrators for surgical planning purposes or efficacy studies. Thecommunication network1800 can further be tied to an Electronic Medical Records (EMR) system to implement health information technology practices. In other embodiments, thecommunication network1800 can be communicatively coupled to HIS Hospital Information System, HIT Hospital Information Technology and HIM Hospital Information Management, EHR Electronic Health Record, CPOE Computerized Physician Order Entry, and CDSS Computerized Decision Support Systems. This provides the ability of different information technology systems and software applications to communicate, to exchange data accurately, effectively, and consistently, and to use the exchanged data.

Thecommunications network1800 can provide wired or wireless connectivity over a Local Area Network (LAN)1801, a Wireless Local Area Network (WLAN)1805, aCellular Network1814, and/or other radio frequency (RF) system. TheLAN1801 andWLAN1805 can be communicatively coupled to theInternet1820, for example, through a central office. The central office can house common network switching equipment for distributing telecommunication services. Telecommunication services can include traditional POTS (Plain Old Telephone Service) and broadband services such as cable, HDTV, DSL, VoIP (Voice over Internet Protocol), IPTV (Internet Protocol Television), Internet services, and so on.

Thecommunication network1800 can utilize common computing and communications technologies to support circuit-switched and/or packet-switched communications. Each of the standards forInternet1820 and other packet switched network transmission (e.g., TCP/IP, UDP/IP, HTML, HTTP, RTP, MMS, SMS) represent examples of the state of the art. Such standards are periodically superseded by faster or more efficient equivalents having essentially the same functions. Accordingly, replacement standards and protocols having the same functions are considered equivalent.

Thecellular network1814 can support voice and data services over a number of access technologies such as GSM-GPRS, EDGE, CDMA, UMTS, WiMAX, 2G, 3G, WAP, software defined radio (SDR), and other known technologies. Thecellular network1814 can be coupled tobase receiver1810 under a frequency-reuse plan for communicating withmobile devices1802.

Thebase receiver1810, in turn, can connect themobile device1802 to theInternet1820 over a packet switched link.Internet1820 can support application services and service layers for distributing data fromspinal alignment system100,spinal instrument400, and insertinstrument420 to the mobile device502. Themobile device1802 can also connect to other communication devices through theInternet1820 using a wireless communication channel.

Themobile device1802 can also connect to theInternet1820 over theWLAN1805. Wireless Local Access Networks (WLANs) provide wireless access within a local geographical area. WLANs are typically composed of a cluster of Access Points (APs)1804 also known as base stations.Spinal alignment system100,spinal instrument400, and insertinstrument420 can communicate with other WLAN stations such aslaptop1803 within the base station area. In typical WLAN implementations, the physical layer uses a variety of technologies such as 802.11b or 802.11g WLAN technologies. The physical layer may use infrared, frequency hopping spread spectrum in the 2.4 GHz Band, direct sequence spread spectrum in the 2.4 GHz Band, or other access technologies, for example, in the 5.8 GHz ISM band or higher ISM bands (e.g., 24 GHz, etc.).

By way of thecommunication network1800,spinal alignment system100,spinal instrument400, and insertinstrument420 can establish connections with aremote server1830 on the network and with other mobile devices for exchanging data. Theremote server1830 can have access to adatabase1840 that is stored locally or remotely and which can contain application specific data. Theremote server1830 can also host application services directly, or over theinternet1820.

FIG. 14 depicts an exemplary diagrammatic representation of a machine in the form of acomputer system1900 within which a set of instructions, when executed, may cause the machine to perform any one or more of the methodologies discussed above. In some embodiments, the machine operates as a standalone device. In some embodiments, the machine may be connected (e.g., using a network) to other machines. In a networked deployment, the machine may operate in the capacity of a server or a client user machine in server-client user network environment, or as a peer machine in a peer-to-peer (or distributed) network environment.

The machine may comprise a server computer, a client user computer, a personal computer (PC), a tablet PC, a laptop computer, a desktop computer, a control system, a network router, switch or bridge, or any machine capable of executing a set of instructions (sequential or otherwise) that specify actions to be taken by that machine. It will be understood that a device of the present disclosure includes broadly any electronic device that provides voice, video or data communication. Further, while a single machine is illustrated, the term “machine” shall also be taken to include any collection of machines that individually or jointly execute a set (or multiple sets) of instructions to perform any one or more of the methodologies discussed herein.

Thecomputer system1900 may include a processor1902 (e.g., a central processing unit (CPU), a graphics processing unit (GPU, or both), amain memory1904 and astatic memory1906, which communicate with each other via abus1908. Thecomputer system1900 may further include a video display unit1910 (e.g., a liquid crystal display (LCD), a flat panel, a solid-state display, or a cathode ray tube (CRT)). Thecomputer system1900 may include an input device1912 (e.g., a keyboard), a cursor control device1914 (e.g., a mouse), adisk drive unit1916, a signal generation device1918 (e.g., a speaker or remote control) and anetwork interface device1920.

Thedisk drive unit1916 may include a machine-readable medium1922 on which is stored one or more sets of instructions (e.g., software1924) embodying any one or more of the methodologies or functions described herein, including those methods illustrated above. Theinstructions1924 may also reside, completely or at least partially, within themain memory1904, thestatic memory1906, and/or within theprocessor1902 during execution thereof by thecomputer system1900. Themain memory1904 and theprocessor1902 also may constitute machine-readable media.

Dedicated hardware implementations including, but not limited to, application specific integrated circuits, programmable logic arrays and other hardware devices can likewise be constructed to implement the methods described herein. Applications that may include the apparatus and systems of various embodiments broadly include a variety of electronic and computer systems. Some embodiments implement functions in two or more specific interconnected hardware modules or devices with related control and data signals communicated between and through the modules, or as portions of an application-specific integrated circuit. Thus, the example system is applicable to software, firmware, and hardware implementations.

In accordance with various embodiments of the present disclosure, the methods described herein are intended for operation as software programs running on a processor, digital signal processor, or logic circuitry. Furthermore, software implementations can include, but not limited to, distributed processing or component/object distributed processing, parallel processing, or virtual machine processing can also be constructed to implement the methods described herein.

The present disclosure contemplates a machine readablemedium containing instructions1924, or that which receives and executesinstructions1924 from a propagated signal so that a device connected to anetwork environment1926 can send or receive voice, video or data, and to communicate over thenetwork1926 using theinstructions1924. Theinstructions1924 may further be transmitted or received over anetwork1926 via thenetwork interface device1920.

While the machine-readable medium1922 is shown in an example embodiment to be a single medium, the term “machine-readable medium” should be taken to include a single medium or multiple media (e.g., a centralized or distributed database, and/or associated caches and servers) that store the one or more sets of instructions. The term “machine-readable medium” shall also be taken to include any medium that is capable of storing, encoding or carrying a set of instructions for execution by the machine and that cause the machine to perform any one or more of the methodologies of the present disclosure.

The term “machine-readable medium” shall accordingly be taken to include, but not be limited to: solid-state memories such as a memory card or other package that houses one or more read-only (non-volatile) memories, random access memories, or other re-writable (volatile) memories; magneto-optical or optical medium such as a disk or tape; and carrier wave signals such as a signal embodying computer instructions in a transmission medium; and/or a digital file attachment to e-mail or other self-contained information archive or set of archives is considered a distribution medium equivalent to a tangible storage medium. Accordingly, the disclosure is considered to include any one or more of a machine-readable medium or a distribution medium, as listed herein and including art-recognized equivalents and successor media, in which the software implementations herein are stored.

Although the present specification describes components and functions implemented in the embodiments with reference to particular standards and protocols, the disclosure is not limited to such standards and protocols. Each of the standards for Internet and other packet switched network transmission (e.g., TCP/IP, UDP/IP, HTML, HTTP) represent examples of the state of the art. Such standards are periodically superseded by faster or more efficient equivalents having essentially the same functions. Accordingly, replacement standards and protocols having the same functions are considered equivalents.

The illustrations of embodiments described herein are intended to provide a general understanding of the structure of various embodiments, and they are not intended to serve as a complete description of all the elements and features of apparatus and systems that might make use of the structures described herein. Many other embodiments will be apparent to those of skill in the art upon reviewing the above description. Other embodiments may be utilized and derived therefrom, such that structural and logical substitutions and changes may be made without departing from the scope of this disclosure. Figures are also merely representational and may not be drawn to scale. Certain proportions thereof may be exaggerated, while others may be minimized. Accordingly, the specification and drawings are to be regarded in an illustrative rather than a restrictive sense.

Such embodiments of the inventive subject matter may be referred to herein, individually and/or collectively, by the term “invention” merely for convenience and without intending to voluntarily limit the scope of this application to any single invention or inventive concept if more than one is in fact disclosed. Thus, although specific embodiments have been illustrated and described herein, it should be appreciated that any arrangement calculated to achieve the same purpose may be substituted for the specific embodiments shown. This disclosure is intended to cover any and all adaptations or variations of various embodiments. Combinations of the above embodiments, and other embodiments not specifically described herein, will be apparent to those of skill in the art upon reviewing the above description.

FIG. 15 illustrates components of aspinal instrument2000 in accordance with an example embodiment.Spinal instrument2000 is a more detailed illustration of a non-limiting example ofspinal instrument102 ofFIG. 1,spinal instrument400 ofFIG. 2, andspinal instrument410 ofFIG. 3.Spinal instrument2000 is a measurement device having asensored head2002 that incorporates at least one sensor for measuring a parameter of the spine.Spinal instrument2000 comprisessensored head2002,sensors2008,shaft2010,electronic assembly2024,interconnect2028, and handle2030. In one embodiment, handle2030 is formed bycoupling structures2020 and2022 together. Aproximal end2018 ofshaft2010 couples to a distal end ofhandle2030. A proximal end ofsensored head2002 couples to adistal end2014 ofshaft2010.Handle2030 can be held by a surgeon to guide the instrument into the spine region of a patient to take one or more quantitative measurements.Sensored head2002 can be inserted into the spine region such that thesensors2008 can measure the parameters of interest.Electronic assembly2024 operatively couples tosensors2008 to receive, process, and provide quantitative measurement data. In general,spinal instrument2000 can provide quantitative measurement data of a probed region bysensors2008 mounted on or insensored head2002. The quantitative data can also support the installation of a component into the muscular-skeletal region. Quantitative data or information related to the procedure can be displayed on aninterface2038 that may be included inspinal instrument2000. Alternatively,spinal instrument2000 can provide quantitative data in support of a procedure through a remote system as disclosed herein. The remote system can be wired or wirelessly coupled tospinal instrument2000. The quantitative data can be provided in real-time with visualization of the procedure.

In the example,sensored head2002 comprises asupport structure2004 and asupport structure2006.Support structures2004 and2006 can move in relation to one another. For example, a compressive force can be applied to external surfaces ofsupport structures2004 and2006.Structures2004 and2006 can move under the compressive force resulting in a change of height ofsensored head2002. In general, the external surfaces ofsupport structures2004 and2006 would move closer together as the applied force or pressure increases. In one embodiment, the movement or change in distance between the external surfaces ofsupport structures2004 and2006 is small in relation to the height ofsensored head2002 when no compressive force is applied.

Sensors2008 are shown disassembled fromsensored head2002.Sensors2008 are placed withinsensored head2002 when assembled.Sensors2008 couple between interior surfaces ofsupport structures2004 and2006. A compressive force, pressure, or load applied to exterior surfaces ofsupport structures2004 and2006 couples tosensors2008. A measurable parameter of a sensor may directly or indirectly correspond to the force, pressure, or load applied thereto. In oneembodiment sensors2008 are film sensors having a low profile. An example of a film sensor is a piezo-resistive sensor or a polymer sensor. Piezo-resistive film sensors change resistance with an applied force, pressure, or load. Other sensor types can be used as disclosed herein. In general, each sensor is located at a predetermined position withinsensored head2002. The predetermined position can couple to a predetermined location on the external surfaces ofsupport structures2004 and2006. Locating each sensor at a known predetermined position supports the determination of the location of applied load to exterior surfaces ofsupport structures2004 and2006. As shown, four sensors are placed withinsensored head2002. Typically more than one sensor is used to determine location of applied load. The load measurements ofsensors2008 are assessed in relation with the corresponding location of each sensor. For example, the sensor nearest to the applied load will measure the highest load magnitude. Conversely, the sensor farthest from the applied load will measure the lowest load magnitude. Each sensor measurement can be used in the determination of the location where the load is applied to the exterior surfaces ofsupport structures2004 and2006 and the magnitude of the applied load at the identified location.

The resistance of a piezo-resistive film sensor corresponds to the thickness of the film. An applied pressure to piezo-resistive film sensor reduces the thickness thereby lowering the resistance. The surface area of each piezo-resistive sensor is selected to fit withinsensored head2002 and relate to a predetermined location on the external surfaces ofsupport structures2004 and2006 for location identification. The surface area ofsensors2008 corresponds to the range of resistance being measured over the measurable load range ofspinal instrument2000. Typically, the magnitude and change in magnitude of the measurable parameter ofsensors2008 over the specified load range is known or measured.

A voltage or current is typically provided byelectronic assembly2024 to piezo-resistive film sensors. For example, providing a known current to the piezo-resistive film sensor generates a voltage that corresponds to the resistance. The voltage can be measured byelectronic assembly2024 and translated to a load measurement. Similarly, a known voltage can be applied to the piezo-resistive film sensor. The current conducted by the piezo-resistive film sensor corresponds to the resistance of the device. The current can be measured byelectronic assembly2024 and translated to the load measurement. Accuracy of the measurement can be improved by calibration of each sensor and providing the calibration data toelectronic assembly2024 for providing correction to the measured data. The calibration can compare sensor measurements to known loads applied tosensored head2002. Calibration can occur over different operating conditions such as temperature. In one embodiment,sensors2008 may be calibrated as part of a final test ofspinal instrument2000.

As mentioned previously,sensors2008 comprise four sensors that support the measurement of the position of loading applied to at least one of the external surfaces ofsupport structures2004 and2006. In one embodiment,support structures2004 and2006 have convex shaped external surfaces that aid in the insertion ofsensored head2002 into the spinal region such as between vertebrae. The height ofsensored head2002 is a distance between the external surfaces of thesupport structures2004 and2006. Sensored head can be used to distract and generate a gap between vertebrae. For example, the surgeon selects a sensored head of a predetermined height to produce a gap approximately equal to the sensored head height.

Shaft2010 provides a separation distance betweenhandle2030 andsensored head2002. Theshaft2010 allows the surgeon to view anddirect sensored head2002 ofspinal instrument2000 into an exposed area of the spine. Adistal end2014 of theshaft2010 fits into and fastens to aproximal end2016 ofsensored head2002. In one embodiment,shaft2010 is cylindrical in shape and includes at least one lengthwise passage2012.Proximal end2016 ofsensored head2002 can include an opening for receivingdistal end2014 ofshaft2010. Theshaft2010 can be secured in the opening ofsensored head2002 by mechanical, adhesive, welding, bonding or other attaching method. In one embodiment, the attaching process permanently affixessensored head2002 toshaft2010. The lengthwise passage2012 ofshaft2010 may be used to couple a component fromhandle2030 to sensoredhead2002. For example, aninterconnect2028 can couple through the lengthwise passage2012. Theinterconnect2028 extends out of the lengthwise passage2012 on bothdistal end2014 andproximal end2018 ofshaft2010.Interconnect2028couples sensors2008 toelectronic assembly2024. Similarly, a second lengthwise passage inshaft2010 can support a threaded rod that couples to a scissor jack withinsensor head2002 for raising and loweringsupport structures2004 and2006 as disclosed herein. Although a cylindrical shape is disclosed,shaft2010 can be formed having other shapes. In the example,shaft2010 is rigid and does not bend or flex when used to insertsensored head2002 into the spine region. In one embodiment, handle2030,shaft2010,support structure2004, and2006 are formed of a polymer material such as polycarbonate. Alternatively, spinal instrument can comprise metal components or a combination of polymer and metal to form the structure. The metal components can comprise stainless steel.

Handle2030 comprises astructure2020 and astructure2022. Thestructures2020 and2022 can be formed to include one or more cavities, slots, or openings. Acavity2026 is shaped to receiveelectronic assembly2024 that is housed inhandle2030. Thecavity2026 can include one or more features to support and retainelectronic assembly2024. Aslot2032 can be used to guide and retaininterconnect2028 toelectronic assembly2024 for coupling.Structures2020 and2022 couple together to formhandle2030. Anopening2034 on the distal end ofhandle2030 receivesproximal end2018 ofshaft2010. In one embodiment,structures2020 and2022 can be formed of a polymer or metal. In the example,sensored head2002,shaft2010, andstructures2020 and2022 can be formed by a molding process using a polymer material such as polycarbonate. Thestructures2020 and2022 can be fastened together by mechanical, adhesive, welding, bonding or other attaching method. Similarly,proximal end2018 ofshaft2010 can be coupled to opening2034 on the distal end ofhandle2030 by mechanical, adhesive, welding, bonding, or other attaching method. In general, the active circuitry withinspinal instrument2000 is isolated from the external environment and a rigid device is formed whensensored head2002,shaft2010, and handle2030 are coupled together. In one embodiment, the sealing process is permanent andspinal instrument2000 cannot be disassembled to replace components such as the power source (e.g. batteries) that can be included inelectronic assembly2024. Thehandle2030 can be formed having a shape that is ergonomic for positioningspinal instrument2000. Thehandle2030 can include weights placed in interior cavities that improve the feel and balance of the device for the surgical procedure. Reinforcement structures can be added to stiffenspinal instrument2000 thereby reducing device flex. The proximal end ofhandle2030 includes aflange2036 for being tapped by a hammer to aid in the insertion ofsensored head2002 into the spinal region. The flange is sized to accept a standard slap-hammer to aid in the removal of the sensor head from the spinal region.Flange2036 and the proximal end ofhandle2030 are reinforced to withstand hammer taps by the surgeon.

Electronic assembly2024 controls a measurement process ofspinal instrument2000. In the example, the components of the system are mounted to a printed circuit board. The printed circuit board can have multiple layers of interconnect. Components can be mounted on both sides of the printed circuit board. In one embodiment, the printed circuit board includes aconnector2040 for receiving and retaininginterconnect2028. In the example,interconnect2028 can be a flexible planar interconnect having copper traces thereon comprising five interconnects for coupling tosensors2008. A power source such as a battery can be mounted to the printed circuit board for poweringelectronic assembly2024. Communication circuitry ofelectronic assembly2024 can wirelessly transmit measurement data to a remote system for viewing in real-time.Spinal instrument2000 can also receive information or data through a wired or wireless connection.Spinal instrument2000 can includedisplay2038 with a GUI to locally provide data to the surgeon.Spinal instrument2000 can also be operatively coupled via a remote sensor system to allow control or feedback through vocal, visual, haptic, gestures, or other communicative means to simplify a workflow or reduce staff required for the procedure.

FIG. 16 illustrates aspine measurement system2100 for providing intervertebral load and position of load data in accordance with an example embodiment.Spine measurement system2100 is a more detailed illustration of a non-limiting example ofspine measurement system100 ofFIG. 1.System2100 can also include an insert instrument and external alignment devices. Thesystem2100 comprisesspinal instruments2102A-F (2102A,2102B,2102C,2102D,2102E, and2102F) that include active circuitry for measuring a parameter of the muscular-skeletal system.Spinal instruments2102A-F are a non-limiting example ofspinal instrument400 ofFIG. 2,spinal instrument410 ofFIG. 3, andspinal instrument2000. In the example,spinal instruments2102A-F each include one or more sensors to measure load and position of load.

Thesystem2100 comprises a set ofspinal instruments2102A-F where each tool has a different distraction height. Spinal instruments can also be provided having sensored heads of different lengths. As shown, the set ofspinal instruments2102A-F have asensored head length2120. An example of sensored heads having different head lengths is disclosed below and can be adapted tosystem2100. Eachspinal instrument2102A,2102B,2102C,2102D,2102E, and2102F respectively has sensoredheads2104A,2104B,2104C,2104D,2104E, and2104F. The surgeon selects the spinal instrument for an appropriate sensored head height that distracts a spinal region appropriate for a patient physiology. As shown, the sixsensored heads2104A,2104B,2104C,2104D,2104E, and2104F respectively have heights A, B, C, D, E, and F. The six different heights A-F of sensored heads2104A-F are an example of what might be provided in a typical system. An example of a distraction height range for a set of sensored heads can be from 6 millimeters to 14 millimeters. An example range of the length of a sensored head can be from 22 millimeters to 36 millimeters. In general, the different height and lengths of sensored heads2104A-F ofsystem2100 are chosen to cover a statistically significant portion a patient population a surgeon is likely to see. The actual number of sensored heads having different height and lengths can vary depending on the application. In one embodiment, sensored head height and lengths that are out of the norm can be inventoried in the operating room but may not be part of the set provided initially during the procedure. The inventoried sensored heads can be made available to the surgeon in the event that the set does not provide a suitable sensored head height and length for the patient.

In general,spine measurement system2100 measures a parameter of the spinal region. In the example, load and position of load are measured.Spinal instruments2102A-F can also measure the location and position in 3D space with one or more internal accelerometers within each tool. In one embodiment, an accelerometer identifies the trajectory, location and position of the sensored head in real-time. The accelerometer can be located in the handle ofspinal instruments2102A-F with the electronic assembly. The one or more parameter measurements output bysystem2100 provide quantitative data to support the procedure. For example, the surgeon exposes the spinal region and views the area of interest. Thespinal instruments2102A-F is made available such that the surgeon can select and use at least one of the tools.Remote system105 is typically placed outside the sterile field of the operating room. In one embodiment, eachspinal instrument2102A-F may be stored in individual sterilized packaging that is not opened until the surgeon views the spinal region being repaired. The selection of a spinal instrument is patient specific due to variations in spine gap and patient physiology. In the example, the surgeon first determines the appropriate gap height and then opens a sterile package having the spinal instrument with the sensored head of the selected height. In one embodiment, the selected spinal instrument can be placed by a device that can initiate a power up sequence. The enabling process couples an internal power source of the tool to the electronic circuitry and sensors therein. Once powered up, the selected spinal instrument can be coupled toremote system105.Remote system105 receives and displays data from the selected spinal instrument.Remote system105 includes aGUI107 for controlling user interaction and providing data on a display. TheGUI107 can provide different screens or windows at different steps of the procedure as a workflow that provides quantitative data to the surgeon in one or more formats such that the data supports the surgical outcome.

The surgeon holds the selected spinal instrument by the handle and directs the sensored head between the vertebrae. The enabled spinal instrument sends load, position of load, instrument position, and location data to theremote system105 where it is displayed in real-time. As mentioned herein, the exterior surfaces of the sensored head are convex in shape such that the tip is narrowed allowing penetration between a separated space between vertebrae prior to distraction. The amount of force required to distract vertebrae can vary. A controlled force applied to the selected spinal instrument may be required to increase the opening between vertebrae. For example, a hammer can be used to tap the flange at the end of the handle of the selected spinal instrument to insert the sensored head between the vertebrae.

In the example, the final position of the sensored head corresponds to the location where a component such as a spinal cage can be placed in a subsequent step. The spinal cage would have a height and length substantially equal to the height and length of the sensored head of the selected spinal instrument.System2100 measures and displays quantitative data from the selected spinal instrument such as trajectory, position, location, loading, and position of loading of the sensored head. The data supports the placement of the component in the location. More specifically, the loading and position of load on the component placed between the vertebrae can be substantial equal to the quantitative measurements from the selected spinal instrument when the component is placed and located in the final position of the sensored head when distracting the vertebrae.

The surgeon may find that the selected spinal instrument has a sensored head height that is larger or smaller than needed. The surgeon uses as many spinal instruments as required to distract the vertebrae to an appropriate height. This similarly applies to the selection of spinal instruments of different lengths. In one embodiment, the power source within eachspinal instruments2102A-F can power the tool for only a single procedure. Moreover,spinal instruments2102A-F may not be capable of being sterilized for reuse without compromising the integrity of the device. The spinal instruments that have been removed from sterilized packaging can be disposed of after the surgical procedure is performed. The spinal instruments that remain in sterile packaging can be used in another procedure. The spinal instruments that are disposed of after being used can be replaced to complete the set.

An alternate approach can use a passive set of spinal instruments to do the initial distraction. The passive spinal instruments have no measurement capability. The surgeon identifies an appropriate distraction height between vertebrae with the passive spinal instruments. The set of passive spinal instruments have heads with equal heights asspinal instruments2102A-F. A spinal instrument is then selected fromspinal instruments2102A-F having a height equal to the identified distraction height made by the passive spinal instrument. The selected spinal instrument is then inserted between the vertebrae. Quantitative data measurements are then taken by the selected spinal instrument in preparation for implanting a component between the vertebrae. The passive spinal instruments can also be low cost disposable or tools that can be sterilized after use. The alternate approach provides the benefit of minimizing the number ofspinal instruments2102A-F used in the procedure.

A method of providing spinal instruments to an operating room is disclosed below. The steps of the method can be performed in any order. The example comprises a system that includes more than one spinal instruments having active circuitry for measurement of a spinal region. The non-limiting example is used to demonstrate a method that is applicable to other muscular-skeletal regions such as the knee, hip, ankle, spine, shoulder, hand, arm, and foot. In a first step, more than one spinal instrument is provided within the operating room. The spinal instruments are in individually sterilized packaging. In one embodiment, the spinal instruments each have a different distraction height and length. The surgeon exposes the spinal region and assesses the patient physiology. In a second step, one of the spinal instruments is selected. In the example, the spinal instrument is selected having an appropriate distraction height for the patient. The spinal instrument is used to measure a parameter of the spinal region such as load and position of load. In a third step, the selected spinal instrument is removed from the sterilized packaging. In a fourth step, the selected spinal instrument is enabled. In the example, the enabling process couples an internal power source to the circuitry in the selected spinal instrument thereby powering up the device for generating quantitative measurement data.

Powering up the selected spinal instrument enables communication circuitry within the device. In a fifth step, the selected spinal instrument couples to a remote system. In the example, the remote system is in the operating room within viewing range of the surgeon. The remote system includes a display for presenting the quantitative measured data from the selected spinal instrument. The remote system can indicate that the selected spinal instrument is enabled by audio, visual, or haptic feedback.

The distraction height can be determined using passive spinal distraction instruments prior to selecting the active spinal instrument. The surgeon selects a passive spinal instrument after the spine region is assessed or exposed. In a sixth step, the spinal region is distracted using the selected passive spinal instrument. The passive spinal instruments have no active circuitry for measurement. In the example, a set of passive spinal instruments has identical heights and lengths as the set of active spinal instruments. In a seventh step, the passive spinal instrument is removed from the spinal region after distraction with the selected passive spinal instrument. In an eighth step, the selected spinal instrument is inserted in the spinal region previously distracted by the selected passive spinal instrument. In the example, the selected spinal instrument has the same height and length as the selected passive spinal instrument. In a ninth step, the selected spinal instrument takes parameter measurements. The data can be wirelessly transmitted to a remote system for display or visualization of the procedure.

One or more of the active spinal instruments can be used during the procedure. In a tenth step, the active spinal instruments that were used to take measurements of the spinal region are disposed of after the procedure. In one embodiment, the passive spinal instruments can go through a sterilization process and are not disposed. Alternatively, the used passive spinal instruments can be disposed similar to the active spinal instruments. In an eleventh step, the spinal instruments that were used and disposed of are replaced. The replacements re-complete the set for a subsequent procedure. The remaining active spinal instruments that were not used are sterile as their sterilized packaging was not opened during the procedure and thus can be reused.

FIG. 17 illustrates aspine measurement system2200 for providing intervertebral load and position of load data in accordance with an example embodiment.Spine measurement system2200 is a more detailed illustration of a non-limiting example ofspine measurement system100 ofFIG. 1. Thesystem2200 comprises aremote system105 and a modular spinal instrument.System2200 can also include an insert instrument and external alignment devices. The modular spinal instrument comprises ahandle2206, ashaft2208, a plurality of removable sensored heads2204A-F, and amodule2210. In general, the spinal instrument is a modular active device having components that can be coupled to handle2206 andshaft2208. Three sets of removable sensored heads2204A-F (2204A,2204B,2204C,2204D,2204E, and2204F),2216A-F (2216A,2216B,2216C,2216D,2216E, and2216F), and2218A-F (2218A,2218B,2218C,2218D,2218E, and2218F) are shown insystem2200. There can be more or less than three sets of sensored heads provided insystem2200. Sensored heads2204A-F,2216A-F, and2218A-F can be coupled to or removed from the distal end ofshaft2208. Similarly,module2210 can be coupled to or removed from acavity2214 ofhandle2206. An external surface ofmodule2210 can be shaped as part of an exterior surface ofhandle2206 when attached.Module2210 includes anelectrical assembly2212 comprising electronic circuitry for receiving, processing, and sending quantitative data from sensors in a sensored head.Module2210 can also include a power source for poweringspinal instrument2202 during a procedure. Electrical interfaces andinterconnect couple module2210 to one of sensored heads2204A-F when respectively assembled to handle2206 andshaft2208.

In general, sensored heads of different heights and different lengths are provided as part of the system for supporting spine measurements over a large statistical population of spine anatomy. The concept can be applied to the configuration disclosed inFIG. 16 where additional sets of spinal instruments can be provided having different sensored head lengths. The modular spinal instrument is a measurement device and a distractor. Removable sensored heads2204A,2204B,2204C,2204D,2204E, and2204F respectively have a sensored head height of A, B, C, D, E, and F. Similarly, removable sensored heads2216A,2216B,2216C,2216D,2216E, and2216F and2218A,2218B,2218C,2218D,2218E, and2218F respectively have head height A, B, C, D, E, and F. The six different heights A-F ofsensored heads2204A-F are an example of what might be provided in a typical system. Each set can set can have more or less than the number of heights show. As mentioned previously, an example range for sensored head heights can be 6 millimeters to 14 millimeters. Sensored heads2204A-F,2216 A-F, and2218A-F respectively have a sensored head length of2220,2222, and2224. The surgeon selects the appropriate sensored head length based on the patient spine anatomy. An example range for sensored head lengths can be from 22 millimeters to 36 millimeters.

The actual number of sensored heads having different heights can vary depending on the application. In one embodiment, sensored head height and length that are out of the norm can be inventoried in the operating room but may not be part of the set provided within the surgical field of the operating room. They can be made available to the surgeon in the event that the set does not provide a suitable sensored head height and length for the patient. The sensored head ofspinal instrument2202 is inserted in the spinal region thereby generating a gap or spacing approximately equal to the height of the sensored head. Spinal instrument2202A-F is a non-limiting example ofspinal instrument400 ofFIG. 2 andspinal instrument410 ofFIG. 3. In the example, spinal instruments2202A-F includes one or more sensors to measure load and position of load.

In general,system2200 can be used in an operating room to provide quantitative measurements on the spinal region. A surgeon exposes and reviews the spinal region prior to distraction. The surgeon may select one of the sets ofsensored heads2204A-F,2216A-F, and2218A-F respectively having thesensored head lengths2220,2222, and2224. For example, the surgeon chooses the set of sensored heads2204A-F having theshortest head length2220. The surgeon can then select one of sensored heads2204A-F having a height that distracts the spinal region appropriate for a patient physiology. In one embodiment, sensored heads2204A-F are in individual sterilized packaging. The selected sensored head is removed from the individual sterilized packaging. The surgeon couples the selected sensored head to the distal end ofshaft2208. Similarly,module2210 is removed from sterilized packaging and installed inhandle2206.System2200 is then enabled for providing quantitative data fromspinal instrument2202. The enabling process can couple an internal power source of the tool to the electronic circuitry and sensors therein. Once powered up, the selected spinal instrument can be coupled toremote system105.Remote system105 will provide indication thatspinal instrument2202 is enabled and operating.Remote system105 receives and displays data from the selected spinal instrument.Remote system105 includes aGUI107 for initiating a workflow, controlling user interaction, and providing data on a display. TheGUI107 can provide different screens or windows at different steps of the procedure as a workflow that provides quantitative data to the surgeon in or more formats such that the data supports the surgical outcome.

The surgeon during the procedure may find that the selected sensored head has a height that is larger or smaller than needed.Spinal instrument2202 can be removed from the spinal region to replace the sensored head. The sensored head can be replaced as many times as necessary until an appropriate distraction height is achieved and the quantitative measurements ofspinal instrument2202 provide assessment of the spinal region. In one embodiment, the power source withinmodule2210 can power the tool for a single surgical application.Module2210 can be sealed to prevent replacement of the power source. Furthermore, after a completed procedure,module2210 and used sensored heads2204A-F are disposed of in a manner to prevent reuse. A complete set of sensored heads2204A-F can be made for a subsequent procedure by replacing the used sensored heads and combining with the unused remaining sensored heads2204A-F. Spinal instrument2202 provides the benefit of lowering cost by replacing only a portion of the system.

A method of measuring a spinal region is disclosed below. The steps of the method can be performed in any order. The example comprises a spinal instrument having active circuitry for measuring a parameter, position, and trajectory. The spinal instrument can be used to distract the spinal region. The spinal instrument is modular allowing rapid changes during a procedure to change a distraction height. The non-limiting example is used to demonstrate a method that is applicable to other muscular-skeletal regions such as the knee, hip, ankle, spine, shoulder, hand, arm, and foot.

In a first step, one of a plurality of removable sensored heads is selected. The plurality of sensored heads comprises a set where each sensored head has a different height. One or more sets of sensored heads can be provided where the sensored heads of a set have a different head length than the other sets. In one embodiment, each sensored head is in an individual sterilized package. The selected sensored head is removed from the sterilized packaging. In a second step, a selected sensored head is coupled to a distal end of a shaft of the instrument. In one embodiment, the sensored head and the shaft respectively have a female and male coupling. The male coupling is inserted into the female coupling and locked into place. The locking step can be a rotation of the sensored head to a position that includes one or more retaining features. In a third step, a module is coupled to the spinal instrument. The module includes an electronic assembly for receiving data from sensors in the sensored head. In one embodiment, the module is placed in a cavity of the handle. The module includes a retaining feature that locks it into place in the handle but allows removal of the module. The electronic assembly operatively couples to the sensored head via electrical interfaces and interconnect in the instrument. The instrument can be enabled for taking measurements during the distraction process.

In a fourth step, the sensored head on the instrument is removed. In one embodiment, the active circuitry in the instrument is disabled prior to the sensored head removal process. In the example, the sensored head is rotated back from the locked position such that the shaft can be withdrawn. In a fifth step, a sensored head is selected from the remaining sensored heads. Typically, the previous sensored head is replaced to select a different distraction height based on the patient physiology. As before, the newly selected sensored head is removed from the individualized sterilized packaging. In a sixth step, the newly selected sensored head is coupled to the distal end of the shaft of the instrument as disclosed above. In a seventh step, the instrument is enabled for generating quantitative measurement data on the muscular-skeletal system. The process of enabling couples a power source within the module to the electronic assembly to power the instrument. In one embodiment, the power source is disconnected from the electronic assembly while in the sterilized packaging to prevent discharge and maximize life. In an eighth step, the used sensored heads and the module are disposed of after a procedure. The sensored head and the module are removed from the instrument and disposed of appropriately. In one embodiment, the main body of the instrument comprising the handle and shaft can be sterilized for a subsequent procedure.

FIG. 18 illustrates an exploded view ofmodule2210 and handle2206 in accordance with an example embodiment.Module2210 and handle2206 are part ofspinal instrument2202 ofFIG. 17. Reference can be made to components ofFIG. 17 andFIG. 18. Aremovable module2210 is a non-limiting example that can be applied to instruments and tools described herein to lower system cost and provide a performance upgrade path.Module2210 comprises anelectronic assembly2212 for receiving, processing, and sending measurement data from sensors in the sensored head ofspinal instrument2202.Electronic assembly2212 corresponds toelectronic assembly2024 ofFIG. 15 and includes at least some of the circuitry described inFIG. 11 andFIG. 12.Electronic assembly2212 is sealed withinmodule2210 and is isolated from an external environment.Module2210 couples to and is removable fromspinal instrument2202. In general,spinal instrument2202 includes an electrical interface that couples tomodule2210. In the example,spinal instrument2202 includes acavity2214 for receivingmodule2210. Anelectrical interface2308 incavity2214 couples to and aligns with electrical interface2302 whenmodule2210 is inserted. In one embodiment,electrical interfaces2302 and2308 are held together under pressure to ensure electrical coupling of each interface. For example,electrical interface2308 can include spring contacts that compress under insertion ofmodule2210 to maintain coupling under force. Aflexible interconnect2310 couples toelectrical interface2308 incavity2214 ofhandle2206.Flexible interconnect2310 extends through the shaft ofspinal instrument2202 for coupling to sensors in a sensored head region of the device.

In the example,module2210 can be made from a polymer material such as polycarbonate.Module2210 can be molded in two or more pieces and assemble together to form a housing or enclosure.Electronic assembly2212 can be placed in a molded cavity that retains and orients the circuitry withinmodule2210.Electronic assembly2212 can be coupled to electrical interface2302 using a flexible interconnect.Electronic assembly2212 and electrical interface2302 can include one or more connectors that couple to the flexible interconnect to simplify assembly. The remaining molded pieces can be attached to form the housing or enclosure using sealing methodologies such as adhesives, welding, mechanical fastening, or bonding. In one embodiment, wireless communication is used to send measurement data fromspinal instrument2202 to a remote system for display and visualization. A polymer material such as polycarbonate is transmissive to wireless signals allowing the measurement data to be transmitted from withinmodule2210 through the enclosure.

Module2210 further includes afeature2304 to align and retain the device when coupled tospinal instrument2202.Feature2304 fits intoopening2312 whenmodule2210 is inserting intocavity2214 ofhandle2206. A locking mechanism is shown in an opposing view ofmodule2210. The locking mechanism comprises aflexible tab2306 having aflange2316 that extends fromtab2306.Flange2316 corresponds and fits intoopening2314 incavity2214 ofhandle2206. Thefeatures2304 and2316 respectively inopenings2312 and2314 retain and preventmodule2210 from disengaging during use ofspinal instrument2202. A removal process ofmodule2210 requiresflexible tab2306 to be flexed such thatflange2316 is removed fromopening2214.Module2210 can then be disengaged fromcavity2214 while bendingflexible tab2306 to preventflange2316 from coupling toopening2314.

FIG. 19 illustrates ashaft2404 for receiving aremovable sensored head2402 in accordance with an example embodiment. The illustration shows a detailed view ofsensored head2402 and adistal end2404 ofshaft2208 ofFIG. 17. Reference can be made to components ofFIG. 17 andFIG. 18.Sensored head2402 corresponds to sensoredheads2204A-F ofFIG. 17 for providing an example of a removable sensored head fromspinal instrument2202. In general, a proximal end ofsensored head2402 includes a coupling that mates with a coupling on thedistal end2404 ofshaft2208 of the tool. The couplings mate together to physically attachsensored head2402 andshaft2208 for a distraction and measurement process. The coupling on the proximal end ofsensored head2402 and the coupling ondistal end2404 ofshaft2208 when attached form a rigid structure that can be inserted in the spinal region and moved to position the device under load.Sensored head2402 includes one or more sensors for measuring a parameter of the spinal region. The sensors can be coupled by a flexible interconnect withinsensored head2402 to an electrical interface in proximity to the coupling onsensored head2402. Similarly, an electronic assembly can be coupled to an electrical interface on thedistal end2404 ofshaft2208 by a flexible interconnect that extends through a lengthwise passage ofshaft2208. The electrical interfaces ofsensored head2402 anddistal end2404 ofshaft2208 align and couple the electrical assembly to the sensors when attached together by the couplings. Thus,sensored head2402 can be removed and replaced when required during the procedure.

A female coupling is accessible through anopening2406 at a proximal end of thesensored head2402 in the example attachment mechanism. Amale coupling2408 extends fromdistal end2404 ofshaft2208. Themale coupling2408 comprises acylindrical extension2414 having a retainingfeature2416. The coupling types can be reversed such that the male coupling is onsensored head2402 and the female coupling ondistal end2404 ofshaft2208. Anelectrical interface2410 can be formed on the distal end ofshaft2404.Male coupling2408 extends centrally fromelectrical interface2410.Electrical interface2410 includes spring-loadedpins2412 for electrical coupling and seals thedistal end2404 ofshaft2208. Spring-loadedpins2412 are located on a periphery ofelectrical interface2410 aroundmale coupling2408. Spring loadedpins2412 couple to a flexible interconnect withinshaft2208. Spring loadedpins2412 can compress under pressure applied by the attaching process. The force applied by spring loadedpins2412 to the corresponding electrical interface onsensored head2402 ensures reliable electrical coupling from sensors to the electrical assembly when attached. Spring-loadedpins2412 include a gasket or seal to isolate an interior ofshaft2208 from an external environment. In one embodiment,electrical interface2410 can be sealed allowing sterilization ofshaft2404 and handle2206 for reuse in a subsequent procedure. As shown, there are five spring-loadedpins2412 onelectrical interface2410. The five pins couple to four sensors insensored head2402 and ground. In the example, the four sensors measure load and position of load applied by the spinal region to the exterior surfaces ofsensored head2402.

FIG. 20 illustrates a cross-sectional view of afemale coupling2502 ofsensored head2402 in accordance with an example embodiment. In general,male coupling2408 couples tofemale coupling2602 to retainsensored head2402 todistal end2404 ofshaft2208. Reference may be made toFIG. 17,FIG. 18, andFIG. 19.Opening2406 ofsensored head2402 receives thedistal end2404 ofshaft2208.Female coupling2502 includes anelectrical interface2504 that corresponds toelectrical interface2410 ondistal end2404 ofshaft2208.Electrical interface2504 includeselectrical contact points2506 that align to spring loadedpins2412 when sensoredhead2502 is attached todistal end2404 ofshaft2208.Electrical interconnect2508 coupleselectrical contact points2506 to sensors insensored head2402.Female coupling2502 includes akeyed opening2510 that is located centrally on the structure.Keyed opening2510 has a single position that allows retainingfeature2416 to be inserted throughfemale coupling2502.

In one embodiment, the outer diameter ofelectrical interface2410 is approximately equal to or smaller than the inner diameter ofopening2406. The fit ofelectrical interface2410 to opening2406 supports the rigid coupling ofsensored head2402 toshaft2404.Sensored head2402 is rotated after retainingfeature2416 is inserted through keyedopening2510. A spring-loadedbarrier2512 is in a rotation path of retainingfeature2416. Spring-loadedbarrier2512 can compress to approximately surface level of the surface offemale coupling2502. The surface of spring-loadedbarrier2512 can be curved or spherical. Retainingfeature2416 when rotated compresses spring-loadedbarrier2512 and rotates over the structure during the attaching process. The spring in spring loadedbarrier2512 raises the structure back above the surface offemale coupling2502 after retaining feature rotates past. Arotation stop2514 in the rotation path prevents further rotation ofsensored head2402 by blockingretaining feature2416.

In one embodiment, retainingfeature2416 is stopped betweenrotation stop2514 and spring-loadedbarrier2512.Rotation stop2514 and spring loadedbarrier2512 form a barrier to prevent movement and rotation ofsensored head2402 when in use. Furthermore,rotation stop2514 positions sensoredhead2402 such thatelectrical interface2504 andelectrical interface2410 are aligned for coupling sensors insensored head2402 to the electrical assembly for providing sensor measurement data. In general, retainingfeature2416 is held against the surface offemale coupling2502 under force. For example, the rotation path of retainingfeature2416 can be sloped to increase the force between retainingfeature2416 and the surface offemale coupling2502 as it approachesrotation stop2514. Spring loadedpins2412 can also apply a force that presses retainingfeature2416 to the surface offemale coupling2502.

FIG. 21 illustrates an exploded view of aspinal instrument2600 in accordance with an example embodiment.Spinal instrument2600 is a more detailed illustration of a non-limiting example ofspinal instrument102 ofFIG. 1,spinal instrument400 ofFIG. 2, andspinal instrument410 ofFIG. 3.Spinal instrument2600 is a measurement device having asensored head2002 that incorporates at least one sensor for measuring a parameter of a spinal region.Spinal instrument2600 comprises ahousing2602,housing2604,electronic assembly2626,interconnect2630, andsensors2638. In general,housings2602 and2604 couple together to isolateelectronic assembly2626,interconnect2630, andsensors2638 from an external environment.Housings2602 and2604 respectively include asupport structure2610 and asupport structure2616.Sensors2638 couple to supportstructures2610 and2616 to measure the parameter of the spinal region. In a surgical procedure,support structures2610 and2616 can come in contact with the spinal region. In one embodiment,support structures2610 and2616 comprise a sensored head ofspinal instrument2600 that can compresssensors2638 when a compressive force is applied.

Housing2602 comprises ahandle portion2606, ashaft portion2608, and thesupport structure2610. Similarly,housing2604 comprises ahandle portion2612, ashaft portion2614, and thesupport structure2616.Housing2604 further includes aflange2644, acavity2618, and alengthwise passage2646.Flange2644 is a reinforced structure on a proximal end of the handle ofspinal instrument2600.Flange2644 can be struck with a hammer or mallet to provide an impact force to insert the sensored head ofspinal instrument2600 into the spinal region.Cavity2618 supports and retains anelectronic assembly2626.Electronic assembly2626 receives, processes, and sends quantitative measurements fromsensors2638. Apower source2628 couples toelectronic assembly2626. In one embodiment, the power source can be one or more batteries that are mounted on a printed circuit board ofelectronic assembly2626.Electronic assembly2626 can be coupled tosensors2638 by aflexible interconnect2630.Flexible interconnect2630 can comprise a flexible substrate having patterned electrically conductive metal traces.Electronic assembly2626 can have one or more connectors that couple toflexible interconnect2630 to simplify assembly.Flexible interconnect2630 couples through a lengthwise passage in the shaft ofspinal instrument2600. In one embodiment, lengthwisepassage2646 is used as a channel forflexible interconnect2630 that couplescavity2618 to a sensored head region. Retaining features2640 can retainpower source2628,electronic assembly2626, andflexible interconnect2630 in place when assemblingspinal instrument2600. Retaining features2640 can comprise foam that can be coupled to components and compress without damaging active components ashousing2602 is coupled tohousing2604.

The sensored head ofspinal instrument2600 comprisessupport structure2610,support structure2616,interconnect2634,sensor guide2636, andsensors2638. The exterior surfaces ofsupport structures2610 and2616 may be shaped convex to support insertion into the spinal region.Interconnect2634 is a portion offlexible interconnect2630 that overlies an interior surface ofsupport structure2616.Flexible interconnect2634 includes conductive traces that couple to electrical contact regions ofsensors2638.Sensor guide2636 overliesinterconnect2634. In one embodiment,interconnect2634 andsensor guide2636 can be aligned and retained withinsupport structure2616 by a peripheral sidewall.Sensor guide2636 includes openings for retaining andpositioning sensors2638. In the example,sensors2638 are force, pressure, or load sensors.Interconnect2634 can have electrical contact regions that align with the openings ofsensor guide2636. The electrical contact regions are exposed for coupling tosensors2638 through the openings ofsensor guide2636.Sensor guide2636 also retains and positionssensors2638 such that the electrical interface of each sensor can couple to a corresponding electrical contact region ofinterconnect2634. The electrical interface ofsensors2638 can be coupled to the corresponding electrical contact region ofinterconnect2634 by such means as solder, conductive epoxy, eutectic bond, ultrasonic bond, or mechanical coupling.Sensor guide2636 also positions sensors to couple to supportstructure2610 or2616 at predetermined locations. In one embodiment,sensors2638 contact an internal surface ofsupport structure2610 or2616 that correspond to locations on the external surfaces. Positioning the sensors viasensor guide2636 allows the position of the applied load on the external surface ofsupport structure2610 to be calculated. Aload plate2642 can be coupled betweensensors2638 and the interior surface ofsupport structure2610.Load plate2642 distributes loading from the interior surface ofsupport structure2610 to eachsensor2638.

As mentioned previously,housings2602 and2604 when coupled together support compression of the sensored head ofspinal instrument2600. A compressive force applied across the external surfaces ofsupport structures2610 and2616 is directed tosensors2638. Other components such assupport structure2610,support structure2616,load plate2642, andinterconnect2634 in the compression path do not deform under load. In one embodiment,load plate2642 comprises a metal such as steel or stainless steel. A compressible adhesive2624 can be used to couple the periphery ofsupport structures2610 and2616 thereby allowing movement of the sensored head andsensors2638 therein over the measurement range. The compressible adhesive2624 can be an adhesive such as a silicone based adhesive. The adhesive2624 is elastic such that the sensored head returns to an unloaded position or moves to a repeatable unloaded height after being compressed. In one embodiment, a second adhesive2622 is used around a remaining periphery ofhousings2602 and2604 to seal and couple the structures together.Adhesives2622 and2624 are applied prior tocoupling housings2602 and2604 together.Adhesive2622 can be a bonding adhesive such as a glue or epoxy that mates the peripheral surfaces together. In other words, the bonded surfaces coupled by adhesive2622 do not have a range of compression as the surfaces are held in contact to one another by adhesive2622. Alternatively, adhesive2624 can be used around the entire periphery to couplehousings2602 and2604 together.

FIG. 22 illustrates a cross-sectional view of a shaft region ofspinal instrument2600 in accordance with an example embodiment. The shaft region is a cross-sectionalview comprising shaft2608 and2614 respectively ofhousing2602 andhousing2604 coupled together. The illustration provides detail on the coupling ofhousings2602 and2604 that corresponds a portion of the shaft region and a handle region ofspinal instrument2600. Reference can be made to components ofFIG. 21. In general, a housing for the active components ofspinal instrument2600 is formed bycoupling housing2602 tohousing2604. In one embodiment, peripheral surfaces ofhousing2602 andhousing2604 are fastened together using more than one adhesive. The peripheral surfaces ofhousings2602 andhousing2604 mate such that the structures align, form a barrier, and provide surface area for bonding. In the example, aperipheral surface2702 ofhousing2602 has a geometric shape such as a triangular extension. Aperipheral surface2704 ofhousing2604 has a corresponding geometric shape such as a v-shaped groove for receiving the triangular extension. Other tongue and groove geometry can be used such as square, round, or other polygonal shapes. Joints such as a butt-joint or a lap joint can also be used. The profile of the peripheral surfaces of a sensored head region differs fromperipheral surfaces2702 and2704 of the shaft and handle regions. In the example, surfaces of the triangular extension ofperipheral surface2702 contact surfaces of the v-shaped groove ofperipheral surface2704 whenhousings2602 and2604 are coupled together.

As mentioned previously,peripheral surfaces2702 and2704 respectively ofhousings2602 and2604 couple the handle portion and the shaft portion ofspinal instrument2600.Peripheral surface2702 fits intoperipheral surface2704 providing alignment feedback during assembly. Referring toFIG. 21, the handle portion and the shaft portion corresponds to the area where adhesive2622 are applied. In the example, adhesive2622 attaches or bondsperipheral surfaces2702 and2704 together with no play or gap between the surfaces other than the adhesive material. In one embodiment, the handle portion and the shaft portion coupled byperipheral surfaces2702 and2704 cannot be disassembled without damage to the housing due to the bond integrity of the joint. The shape ofperipheral surfaces2702 and adhesive2622 seals and isolates an interior ofspinal instrument2600 from an external environment. As shown, a portion of the distal end of the shaft and the peripheral surfaces ofsupport structures2610 and2616 can have a different profile as disclosed herein. Similarly, other geometric shaped surfaces or curved surfaces can be used forperipheral surfaces2702 and2704.

FIG. 23 illustrates a cross-sectional view of a sensored head region ofspinal instrument2600 in accordance with an example embodiment. The illustration provides detail on the coupling ofsupport structures2610 and2616 corresponding to the sensored head region and a distal portion of the shaft region. Reference can be made to components ofFIG. 21 andFIG. 22. In general, the sensored head region includes at least one sensor for measuring a parameter of the spinal region. In the example, sensors for measuring a force, pressure, or load are coupled betweensupport structures2610 and2616. Thesupport structures2610 and2616 compress the sensors when inserted into the spinal region. The sensors output a signal corresponding to the compression. Thus,support structures2610 and2616 move in relation to one another allowing compression of the sensors.

As shown, the periphery ofhousing2602 andhousing2604 corresponding to supportstructures2610 and2616 of the sensored head region couple together in a manner allowing movement.Support structure2610 ofhousing2602 includes aperipheral surface2802 having a triangular shaped region.Support structure2616 ofhousing2604 includes aperipheral surface2804 having a v-shaped groove. In one embodiment, agap2806 exists betweenperipheral surface2802 andperipheral surface2804 whenhousing2602 is coupled tohousing2604. More specifically, the surfaces of the triangular shaped region ofperipheral surface2802 do not contact the surfaces of the v-shaped groove ofperipheral surface2804 whenperipheral surface2702 ofhousing2602 contactsperipheral surface2704 ofhousing2604 as shown inFIG. 22.Gap2806 allows a compressive force applied to the external surfaces ofsupport structures2610 and2616 to move such that the height of the sensored head region is reduced.Gap2806 is larger than a change in height of the sensors over the measurement range ofspinal instrument2600. Although surfaces are shown as triangular and v-groove shaped in the non-limiting example, surfaces2802 and2804 can take other shapes that supportgap2806 and movement ofsupport structures2610 and2616.

The sensored head region and the portion of the distal end of the shaft corresponds to the area where adhesive2624 shown inFIG. 21. In the example, adhesive2624 elastically attachperipheral surfaces2802 and2804 together.Adhesive2624 fillsgap2806 between theperipheral surfaces2802 and2804.Support structures2610 and2616 form a housing for the sensor assembly ofspinal instrument2600.Adhesive2624 can compress when a load is applied acrosssupport structures2610 and2616. Adhesive2624 rebounds elastically after compression of thesupport structures2610 and2616 thereby returning the sensored head region back togap2806 when unloaded.Filling gap2806 with adhesive2624 seals and isolates an interior of the sensored head region and the distal end of the shaft from an external environment. In one embodiment, adhesive2622 and adhesive2624 are applied at approximately the same time during the assembly process.Adhesive2622 is applied to at least one ofperipheral surfaces2702 and2704 ofFIG. 22. Similarly, adhesive2624 is applied to at least one ofperipheral surfaces2802 and2804.Housing2602 andhousing2604 are then coupled together to form the housing for the active system ofspinal instrument2600.

In one embodiment,support structure2610 andsupport structure2616 can be modified to make the exterior load bearing surfaces flexible. Aperipheral groove3006 is formed in thesupport structure2610. In general the groove is formed circumferentially such that the external load-bearing surface can flex. A force, pressure, or load is directed to sensors underlying the load bearing surface. The flexible support structure load-bearing surface minimizes load coupling that can cause measurement error. For example,grooves3006 reduce load coupling fromperipheral surface2802 to2804. Loading applied to the load-bearing surface ofsupport structure2610 is coupled throughinterior surface3004 to loadsensors2638.Grooves3006 can boundinterior surface3004. A load plate can be used to distribute loading frominternal surface3004 tosensors2636. Similarly, agroove3008 is formed circumferentially insupport structure2616 such that the external load-bearing surface ofsupport structure2616 can flex. A force, pressure, or load applied to the load-bearing surface ofsupport structure2616 is directed throughinterior surface3002 tosensors2638. The load coupling throughsurface2804 tosurface2802 is minimized by the flexible external load-bearing surface ofsupport structure2616.Grooves3008 can boundinterior surface3002.

FIG. 24 illustrates an exploded view of a sensored head region ofspinal instrument2600 in accordance with an example embodiment. In general,support structure2616 includes asidewall2904 havingperipheral surface2804. As shown, theperipheral surface2804 ofsidewall2904 is a v-groove.Interconnect2634 offlexible interconnect2634couples sensors2638 toelectronic assembly2626.Flexible interconnect2634 extends through the shaft ofspinal instrument2600 to the sensored head region. In one embodiment,interconnect2634 can be shaped to fit insupport structure2616.Interconnect2634 overlies an interior surface ofsupport structure2616.Interconnect2634 is positioned, aligned, and retained onsupport structure2616 bysidewalls2904.

As shown,sensor guide2636 overliesinterconnect2634.Sensor guide2636 positions and holds sensors2838. In one embodiment, sensor guide includesopenings2906 for four sensors. The four sensors2838 can determine a load magnitude applied to supportstructures2610 and2616 as well as position of the applied load. Electrical contacts ofsensor2638 couple to corresponding contact regions oninterconnect2634. In one embodiment, eachsensor2638 has two contacts, one of which is a common ground.Openings2906 ofsensor guide2636 align to and expose theunderlying interconnect2634. Moreover,openings2906 show contact regions ofinterconnect2634 for coupling to a sensor. Aload plate2636 can overliesensors2638.Load plate2636 is an optional component for distributing an applied force, load, or pressure applied to supportstructures2610 and2616 tosensors2638.Load plate2636 couples to an interior surface ofsupport structure2610.Load plate2636 can also be positioned and aligned in the sensored head region by sidewalls2904 ofsupport structure2616. Alternatively,support structure2610 can have a retaining feature forload plate2636.

FIG. 25 illustrates a cross-sectional view of an assembled sensored head region ofspinal instrument2600 in accordance with an example embodiment. The illustration provides detail on the stacked assembly withinsupport structures2610 and2616 corresponding to the sensored head region. Reference can be made to components ofFIG. 21,FIG. 23, andFIG. 24.Support structure2616 includessidewall2904 that boundsinterior surface3002. In the example,groove3008 is adjacent to sidewall2904 and bounds surface3002 ofsupport structure2616.Groove3008 promotessupport structure2616 to flex under loading.Flexible interconnect2630 coupleselectronic assembly2626 tosensors2638.Flexible interconnect2630 includesinterconnect2634 that is housed in the sensored head region ofspinal instrument2600.Interconnect2634 includes contact regions for coupling tosensors2638.Interconnect2634 overliesinterior surface3002 ofsupport structure2616.Interconnect2634 is retained, aligned, and positioned within the sensored head region bysidewall3002 ofsupport structure2616.

Sensor guide2636 overliesinterconnect2634.Sensor guide2636 is shaped similar tointerconnect2634.Sensor guide2636 is retained, aligned, and positioned within the sensored head region bysidewall2904 ofsupport structure2616.Sensor guide2636 has openings that align with the contact regions ofinterconnect2634.Sensors2638 are placed in the openings ofsensor guide2636 such that contacts ofsensors2638 couple to contact regions oninterconnect2634. In one embodiment,sensor guide plate2636 comprises a non-conductive polymer material. In the example,sensors2638 extend above a surface ofsensor guide2636 for coupling to loadplate2642 or an interior surface ofsupport structure2610.

Aload plate2642 is an optional component of the stacked assembly.Load plate2642 distributes the force, pressure, or load applied to supportstructures2610 and2616 tosensors2638. In one embodiment,load plate2642 can be shaped similarly to interconnect2634 andsensor guide2634.Load plate2642 overlies and couples tosensors2638. In the example,support structure2610 includes a peripheral sidewall that positionsload plate2642 oversensors2638. In the example,groove3006 is adjacent to the peripheral sidewall ofsupport structure2610 and bounds surface3004 ofsupport structure2610.Groove3006 promotessupport structure2610 to flex under loading. Aninternal surface3004 ofsupport structure2610 couples to loadplate2642.Peripheral surface2802 ofsupport structure2610 is coupled toperipheral surface2804 ofsupport structure2616 in a manner to support movement under a compressive load. In particular,sensors2638 can change in height under loading. As disclosed above, elastic adhesive2624 fills a gap betweenperipheral surfaces2802 and2804. Adhesive2624 couples supportstructures2610 and2616 together. The adhesive2624 seals and isolates the stacked assembly of the sensored head region from an external environment. Moreover, adhesive2624 can compress such that a force, pressure, or load applied to supportstructures2610 and2616 translates from the external surfaces tosensors2638 for measurement.

While the present invention has been described with reference to particular embodiments, those skilled in the art will recognize that many changes may be made thereto without departing from the spirit and scope of the present invention. Each of these embodiments and obvious variations thereof is contemplated as falling within the spirit and scope of the invention.

Claims (19)

What is claimed is:

1. An orthopedic measurement device for a knee region comprising:

a first housing component comprising a first handle portion, a first shaft portion, and a first head portion;

a second housing component comprising a second handle portion, a second shaft portion, and a second head portion wherein the first and second housing components couple together to form a device handle, a device shaft, and a device head; and

a first sensor in the device head, where the first sensor is configured to measure a parameter of the knee region, wherein the device handle includes a second sensor, where the second sensor is configured to measure trajectory, location and position of the device head in real-time while the device head is moved toward and within the knee region.

2. The measurement device ofclaim 1 further including:

a cavity in the handle;

an electronic assembly in the cavity; and

a power source coupled to the electronic assembly.

3. The measurement device ofclaim 2 wherein one or more retaining features retain the electronic assembly in the cavity.

4. The measurement device ofclaim 2 wherein a removeable module comprising the electronic assembly and the power source fits within the cavity and forms a portion of the handle.

5. The measurement device ofclaim 1 wherein the first and second housing components comprise polycarbonate.

6. The measurement device ofclaim 1 further including: at least one channel in the shaft from the handle to the head; and

a flexible interconnect in the channel of the shaft coupling the first sensor to the electronic assembly.

7. The measurement device ofclaim 6 wherein the electronic assembly comprises:

a printed circuit board;

electronic circuitry mounted on the printed circuit board; and

one or more connectors coupled to the electronic circuitry wherein the flexible interconnect couples to the one or more connectors.

8. The measurement device ofclaim 1 wherein the first and second housing components each include corresponding mating surfaces that couple together.

9. The measurement device ofclaim 1 wherein a gap exists between a peripheral surface of a first support structure of the head and a peripheral surface of a second support structure of the head when coupled together.

10. The measurement device ofclaim 9 wherein peripheral surfaces of the first and second support structures comprise corresponding triangular shaped region and a v-groove.

11. The measurement device ofclaim 1 wherein the device head includes:

a load plate coupled to the device head; and

a plurality of load sensors coupled to the load plate configured to measure load and position of load wherein the load plate is configured to distribute load applied to the device head to each of the load sensors.

12. The measurement device ofclaim 11 wherein the device head further includes:

a retaining structure coupled to the plurality of load sensors; and

a flexible interconnect coupled to the plurality of load sensors.

13. A spinal instrument for measuring load in a spinal region comprising:

a first housing component comprising a first handle portion, a first shaft portion, and a first head portion;

a second housing component comprising a second handle portion, a second shaft portion, and a second head portion wherein the first and second housing components couple together to form a device handle, a device shaft, and a device head of the spinal instrument, where the first handle connects to the second handle to form a device handle, where the first shaft connects to the second shaft to form a device shaft, where the first head connects to the second head to form a device head; and

a plurality of sensors coupled to a first support structure and a second support structures of the head of the spinal instrument configured to measure load magnitude and position of load applied thereto and wherein the device handle of the spinal instrument includes a second sensor, where the second sensor is configured to measure trajectory, location and position of the device head in real-time while the device head is moved toward and within the spinal region.

14. The spinal instrument ofclaim 13 further including a cavity in the handle;

an electronic assembly in the cavity; and

a power source coupled to the electronic assembly.

15. The spinal instrument ofclaim 14 further including: a removeable module comprising the electronic assembly and the power source fits within the cavity and forms a portion of the handle.

16. The spinal instrument ofclaim 13 wherein a gap exists between a peripheral surface of the first support structure of the head and a peripheral surface of the second support structure of the head when coupled together.

17. The spinal instrument ofclaim 13 wherein peripheral surfaces of the first and second support structures comprise corresponding triangular shaped region and a v-groove.

18. The spinal instrument ofclaim 17 wherein an elastic adhesive couples the mating surfaces together thereby allowing the head of the spinal instrument to compress under a load applied thereto.

19. The spinal instrument ofclaim 18 wherein a non-elastic adhesive couples a portion of the first housing component to the second housing component.

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